The Rise of Nanotechnology | CAS Inquire

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01/30/2020 Added

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Physicist Christian Binek gives the talk "The Rise of Nanotechnology: Small Machines with Big Impact" for the CAS Inquire program's theme "Rise of the Machines." cas.unl.edu/cas-inquire

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[00:00:02.690]It's all about
[00:00:04.190]rise of the machines.
[00:00:06.330]My particular task will be to talk about
[00:00:09.610]the nano machines and the nanotechnology.
[00:00:13.040]So you know that saying, it's about the small things
[00:00:16.700]in life that matter and I guess here,
[00:00:18.560]it's particularly true, so I want to convince you
[00:00:21.550]that small doesn't mean you should look down on it.
[00:00:25.070]It's actually supposed to have a very powerful impact.
[00:00:28.530]Now already, and more so in the future.
[00:00:31.780]So let me give you an out look of this of this presentation.
[00:00:34.520]I will start with,
[00:00:37.700]if you like the grandfather
[00:00:38.700]of this entire idea with Richard Feynman,
[00:00:42.100]the genius who introduced the idea of nanotechnology.
[00:00:46.380]I will give a brief
[00:00:48.840]introduction to the nano scale
[00:00:51.271]so that we get a little bit better a sense
[00:00:53.440]of what that really means, how small that is.
[00:00:56.530]Then I come to important points.
[00:00:58.883]Basically making the point that
[00:01:01.360]nano is more than just small.
[00:01:03.040]It's also small but more than just small.
[00:01:05.150]So I'll talk about emerging interface effects
[00:01:07.460]and as a physicist, I'm of course, also particularly
[00:01:10.730]excited about the fact that we can look into
[00:01:14.910]the quantum world and make discoveries there,
[00:01:18.380]with the help of nano science.
[00:01:20.500]Then I move on and talk a little bit about
[00:01:22.980]what nano scientific and nano technological achievements
[00:01:26.900]we have today.
[00:01:28.260]To get there, we must first ask two questions.
[00:01:30.910]How can we fabricate such nanoscopic structures?
[00:01:35.380]How can we characterize them and then we can look
[00:01:38.080]what is there already.
[00:01:39.300]And I will always try to make reference to work done here
[00:01:44.454]at UNL because we play, in fact, at the forefront
[00:01:48.420]of nanotechnology.
[00:01:50.570]In particular, with our centers here,
[00:01:52.846]the Nebraska center frontiers and nano science
[00:01:55.640]and then Rascal nanoscale facility, I frequently
[00:01:58.410]will make reference to that.
[00:02:00.850]And then I give you
[00:02:02.990]an outlook.
[00:02:04.160]I so to say, try to look into the future
[00:02:08.010]and ask what's the next step?
[00:02:11.050]So, nano technology, so 2020.
[00:02:13.410]What's coming next, right?
[00:02:15.410]And one particular aspect of this may very well
[00:02:18.900]be quantum materials and quantum technologies
[00:02:22.130]and again, we here at UNL
[00:02:24.610]strive to hopefully
[00:02:27.180]be in a position to make nationwide
[00:02:29.360]and hopefully, also internationally
[00:02:31.330]a major impact in this new field.
[00:02:34.470]So I try to look a little bit into the future
[00:02:36.560]and then I give an outlook of
[00:02:39.310]where all this together may be going.
[00:02:42.210]Okay, so let's get started with a brief introduction.
[00:02:45.880]For a brief moment I want to share
[00:02:48.840]the stage here with this little fellow.
[00:02:52.050]Where are you?
[00:02:53.841]Hello!
[00:02:55.350]So, I want to emphasize that
[00:02:58.130]although this guy might look,
[00:02:59.630]little bit like a gnome, it's actually a dwarf.
[00:03:03.480]A biker dwarf, all right.
[00:03:06.079]Some of my friends are bikers,
[00:03:07.280]so they look like this in fact.
[00:03:09.900]So, why do I make reference to dwarfs?
[00:03:14.265]Well a dwarf is a small person, right?
[00:03:16.640]And as a matter of fact,
[00:03:19.792]dwarf
[00:03:21.720]in Greek
[00:03:23.330]means nanos.
[00:03:25.382]And that's obviously where this word 'nano'
[00:03:28.583]originally comes from.
[00:03:30.340]So it describes something small.
[00:03:33.600]I'm asking with the guy, Democritus,
[00:03:38.430]who was already
[00:03:39.290]thinking about the very small building blocks, the atoms.
[00:03:42.590]You can't recognize him because of the sunglasses obviously.
[00:03:47.209]So.
[00:03:48.880]The next slide will give us a little bit, hopefully,
[00:03:51.100]an introduction into the nano scale,
[00:03:54.630]and what is special about it.
[00:03:56.150]So we need to develop an intuition.
[00:03:58.550]And this one,
[00:04:01.200]I didn't invent it,
[00:04:02.080]but I think it's very useful to get a better idea
[00:04:04.790]of where we are in relation to those different
[00:04:08.320]length scales and time scales, which are not shown here.
[00:04:12.370]That are, one end similar to where we live,
[00:04:15.687]and the other is very, very alien.
[00:04:17.750]So we are humans, obviously, and we are somewhere here.
[00:04:21.650]Two meters or so and we can we have a good grasp of things.
[00:04:25.830]Let's say down to the micrometer scale,
[00:04:27.280]where we can see with optical microscopes,
[00:04:30.370]down to a few thousand meters mountain, something like this.
[00:04:33.910]So this is our domain where we live, where we feel home,
[00:04:37.880]and this is also the domain of the classical world.
[00:04:41.200]The classical physics.
[00:04:42.270]Here you have those phonomania,
[00:04:43.920]which we are very familiar with;
[00:04:45.490]classical waves, classical mechanics,
[00:04:49.210]classical electromagnetism.
[00:04:52.400]None of this is trivial, but we have intuition for it,
[00:04:57.680]and that changes.
[00:04:59.920]It changes in two directions,
[00:05:01.880]when we only focus on length scales,
[00:05:04.750]similar things happen with time scales.
[00:05:06.730]But let's for the moment focus on length scales.
[00:05:09.838]We can go in this direction here, and two things change.
[00:05:14.313]Well the length scale changed,
[00:05:16.180]and on this very, very large length scales
[00:05:18.800]we find that other
[00:05:21.800]phenomenon dominate.
[00:05:23.310]Through which are described not by the
[00:05:25.360]regular classical physics in the sense we know it,
[00:05:29.210]meaning in the limit of low velocities, low gravity.
[00:05:34.260]But we approach a region where things can move very fast
[00:05:38.770]and can have very strong gravitational fields,
[00:05:42.270]and that's where we're on the physics of relativity.
[00:05:46.400]Special and general relativity.
[00:05:49.120]It's general relativity that gives rise to the
[00:05:51.360]length scales structures in the universe, for example.
[00:05:54.540]Very alien to us already to some extent,
[00:05:57.740]because we have to deal with phenomenon like
[00:06:02.410]length construction, time dilation,
[00:06:06.010]and redshifts and things like that.
[00:06:09.600]So we have no good intuition,
[00:06:12.060]but believe me it's getting even worse,
[00:06:14.760]if we go in the other direction.
[00:06:16.540]If we go to the very small,
[00:06:19.560]we are,
[00:06:20.910]again,
[00:06:21.743]we have to deviate from the everyday experience
[00:06:24.840]from the classical world and we encounter phenomena,
[00:06:27.630]that as you know, are associated with quantum mechanics.
[00:06:31.570]And that quantum mechanical phenomena are even weirder,
[00:06:35.920]in some extent, than what happens on the large scale.
[00:06:39.870]So, the nanoscale is here in this diagram.
[00:06:44.720]And, first of all, let's introduce numbers,
[00:06:47.710]in nanometer, if you write it down in scientific notation,
[00:06:51.020]its ten to minus nine meter,
[00:06:53.720]you guys know already what this abstract notation means.
[00:06:59.080]So I used this slide, also, to show equations,
[00:07:02.320]that's why I introduce it here again.
[00:07:04.070]So, ten to the minus nine means
[00:07:07.130]one
[00:07:07.963]over
[00:07:08.796]one
[00:07:09.629]billion.
[00:07:10.462]So we have these nine zeros here.
[00:07:12.372]So, it's billions of a meter.
[00:07:15.480]Great, what does that mean, right?
[00:07:17.720]We have still no clue how to relate to that.
[00:07:22.100]So, let me move on, and let me first give you
[00:07:24.500]my approach to what that means.
[00:07:27.660]I'm proud of it, because I invented it,
[00:07:29.640]although I am not sure how useful it is.
[00:07:31.880]So I bring back this guy.
[00:07:33.080]Actually, I bought it specifically for today.
[00:07:38.888]Here it is, and it will go in my, in my front door
[00:07:42.840]or something like that, later.
[00:07:44.700]But for now we use it, why?
[00:07:47.690]Because the height of this guy is eight inch.
[00:07:50.998]And if it doesn't come from the metric system,
[00:07:54.230]you'll want to convert everything into metric numbers.
[00:07:56.540]If you do science, you do that anyways.
[00:07:58.450]So let's do that.
[00:07:59.840]Eight inch are roughly 20 centimeters.
[00:08:02.610]And 20 centimeters are zero point two meters.
[00:08:05.100]And if you like, you can also convert that into nanometers,
[00:08:08.000]which is 200 million nanometers.
[00:08:11.250]Now, let's do the following exercise.
[00:08:13.640]Let's take 2 hundred million of these guys,
[00:08:18.520]and stick them up.
[00:08:19.965]Which gives a huge pile, right?
[00:08:22.560]And how high would that be, well, if you
[00:08:24.940]pile up two hundred million dwarves of
[00:08:27.750]zero point two meters?
[00:08:29.860]That gives a height of approximately 40,000 kilometers.
[00:08:33.060]This is, purely by chance obviously, approximately
[00:08:38.227]the circumstance of the Earth.
[00:08:41.920]So, depicted like this.
[00:08:43.700]So, what that means is, it gives us the chance to picture,
[00:08:46.505]a little bit of the nanoscale.
[00:08:48.410]Because now we can say, that the height of our dwarf,
[00:08:53.110]relates to the circumference of the entire Earth.
[00:08:56.845]That a nanometer relates to the height of the dwarf.
[00:09:01.770]That may help a little bit, because at least it tells us
[00:09:04.000]one more time that the nanometer is damn small, all right?
[00:09:09.140]But, if you want to do something,
[00:09:11.650]if you want to do nanotechnology,
[00:09:14.490]there might be a better comparison,
[00:09:15.930]more use for a comparison,
[00:09:17.040]how does nano compare on the scale of atoms?
[00:09:21.820]That might be a better question to ask.
[00:09:24.630]Let's see.
[00:09:25.810]So, you have seen, in chemistry for example,
[00:09:29.020]it makes a lot of sense to talk about
[00:09:34.260]what, what the radius of an atom,
[00:09:37.180]or the radius of an ion is,
[00:09:38.597]so you actually do find those things in tables.
[00:09:41.350]Of course, there's a wide variation.
[00:09:45.570]But, roughly speaking, everything on the atomic scale,
[00:09:49.930]is on the ångström scale.
[00:09:51.580]So, a typical atom, a typical atom, what ever that means,
[00:09:55.450]might have a diameter of zero point two nanometers,
[00:09:58.700]or two ångström.
[00:10:00.530]That, in turn means, if you take five of them,
[00:10:04.370]and put them into a row,
[00:10:05.690]you'll roughly get a nanometer.
[00:10:08.260]So, five atoms in a row,
[00:10:09.740]approximately give you a nanometer.
[00:10:13.187]And, that brings us directly to the
[00:10:16.150]approach
[00:10:17.780]which Feynman,
[00:10:18.870]in his infamous Caltech speech,
[00:10:21.720]envisioned, which of Feynman won a Nobel Prize,
[00:10:24.060]not for his work in nanotechnology,
[00:10:25.160]but his achievements in quantum electrodynamics.
[00:10:29.040]But, he defined, basically,
[00:10:30.600]what nanotechnology is.
[00:10:31.820]Which is the engineering of functional systems,
[00:10:34.600]at the molecular scale.
[00:10:36.470]And here is such a functional system one can envision.
[00:10:39.430]A simulation of molecular dynamical simulations,
[00:10:42.390]of obviously something that has function.
[00:10:47.175]A gear here, more that, and you see already
[00:10:50.435]some new features pop up.
[00:10:52.790]You see
[00:10:54.600]a classical
[00:10:55.964]gear,
[00:10:57.673]the components wouldn't
[00:10:59.822]wiggle around, right, but here we have individual atoms,
[00:11:02.580]that you see here.
[00:11:03.713]And if you take into account that the fact that
[00:11:05.433]the atoms are always moving around in the equilibrium
[00:11:08.930]positions.
[00:11:09.763]Frictions change, and all that changes, at the nanoscale.
[00:11:13.620]So this is what we have in mind,
[00:11:16.040]at least one example,
[00:11:17.240]when we talk about nanotechnology.
[00:11:20.457]Okay, so, the next point I want to make,
[00:11:24.240]which is also very important,
[00:11:25.510]that nano is not just small.
[00:11:27.560]It is also small, but it is
[00:11:29.110]far more than just being small.
[00:11:31.210]There are qualitative changes in worth, if you
[00:11:34.440]go from the micro scale to the nano scale.
[00:11:39.550]Let's have an example.
[00:11:41.430]Let's look at the piece of gold,
[00:11:44.090]I wish I had this.
[00:11:45.940]So, this is a nice microscopic piece of gold,
[00:11:49.530]and now let's cut it down.
[00:11:50.910]Cut it down, cut it down.
[00:11:52.890]And the machines we will need at
[00:11:54.670]some point to do that, we will talk about,
[00:11:57.330]but at some point you reach a gold cluster.
[00:12:01.190]Something like this.
[00:12:02.023]And here you can resolve already, of course,
[00:12:05.220]it's just a cartoon.
[00:12:06.250]But you can resolve, already, individually,
[00:12:09.090]gold atoms making up this cluster.
[00:12:12.200]Also, you can see these facets here, typically,
[00:12:15.490]showing that particularly crystalline structures
[00:12:19.090]are energetically favored.
[00:12:21.500]Now, what is so different between such a
[00:12:23.470]tiny piece of gold
[00:12:24.734]and this microscopic piece of gold?
[00:12:27.020]Multiple things are different,
[00:12:28.490]but one is immediately clear,
[00:12:31.620]and that is simply from geometry,
[00:12:35.310]it is clear that the shear number of atoms
[00:12:37.990]you find at the surface of this cluster,
[00:12:41.190]relative to the number of atoms overall,
[00:12:43.980]in the volume of this,
[00:12:45.900]of this,
[00:12:47.040]object.
[00:12:47.873]Let's approximate it as a sphere, for simplicity.
[00:12:51.171]The smaller you make it, the higher
[00:12:53.827]the ratio gets the more atoms you find relative
[00:12:57.430]to the volume number of, you find
[00:12:59.180]at the surface.
[00:13:00.013]Why is that?
[00:13:00.846]Well, we can simply plot the
[00:13:04.090]surface
[00:13:05.196]area
[00:13:06.220]of a sphere, 4 pi r squared,
[00:13:08.290]and put in relation to the volume,
[00:13:10.670]for a third pi, to the power of three.
[00:13:14.240]And then you see, that this ratio
[00:13:17.080]behaves like, it is proportionate to
[00:13:18.660]one over the ratios.
[00:13:19.910]That means, if you go to smaller and smaller
[00:13:21.900]radius,
[00:13:23.400]this ratio
[00:13:24.367]goes up.
[00:13:25.960]It goes up dramatically.
[00:13:27.670]So, there's a certain, a certain radius
[00:13:30.780]where the number of atoms are identical,
[00:13:33.080]and then even the number of surface atoms may win.
[00:13:35.639]You see, it goes up.
[00:13:37.170]So, the message is that the number of surface atoms
[00:13:39.460]goes up dramatically.
[00:13:41.230]That has profound implications, which are not trivia,
[00:13:45.170]in the following sense.
[00:13:47.527]First of all, you have so much surface,
[00:13:49.660]you can do a lot with surface.
[00:13:52.010]You can, for example,
[00:13:54.980]decorate these, these clusters
[00:13:57.860]with molecules and functionalize them,
[00:14:00.510]so that they can do something, the particular molecules
[00:14:03.580]are attached to the surface and then
[00:14:07.010]these clusters, in turn, can attach to some other surfaces.
[00:14:10.860]For example, to the membranes of other cells, for example.
[00:14:14.190]We come to this later.
[00:14:16.120]And, why would those clusters
[00:14:18.710]invite other molecules to be attached?
[00:14:22.890]This has something to do with the fact that,
[00:14:25.380]at the surface, these atoms miss neighbors.
[00:14:29.050]Here's a simple example of a
[00:14:30.750]so-called cubic structure, where an atom
[00:14:33.870]in this crystalline cubic structure would
[00:14:36.100]have six nearest neighbors.
[00:14:38.830]If you suddenly bring this atom to the surface,
[00:14:41.440]you at least miss this one here, right?
[00:14:43.610]So it has less neighbors, to bond with,
[00:14:46.640]and that in turn means it has fair electrons
[00:14:49.320]to bond with something else.
[00:14:51.240]So it changes things.
[00:14:53.120]And, also, it, it changes
[00:14:55.353]the, the, the mechanical properties,
[00:14:58.032]the magnetic properties, the optical properties,
[00:15:01.180]everything changes.
[00:15:02.050]We come to this in a little bit more detail.
[00:15:07.090]So, what we do here is basically,
[00:15:09.260]we change structure.
[00:15:10.457]And I want to go a little bit more into
[00:15:12.440]the detail about this very important
[00:15:14.610]and very fundamental relation.
[00:15:16.370]That is basically the essence of all material science,
[00:15:19.300]if you like.
[00:15:20.580]That is the relation between structure and property.
[00:15:25.559]And that's something I want to stress a little bit more,
[00:15:28.631]from various angles.
[00:15:30.690]Maybe first from a more chemical angle,
[00:15:34.540]not my specialty too much,
[00:15:36.160]but I think it's important.
[00:15:38.880]So let's have a look, and let's focus on
[00:15:41.570]carbon, the various forms of carbon you can find.
[00:15:45.950]Well, there are things we are very familiar with,
[00:15:48.120]this one for example, graphite.
[00:15:51.130]Here you have these sheets of carbon atoms,
[00:15:55.740]that are strongly bonded with covalent bonds,
[00:15:58.081]here and then these dashed lines indicate
[00:16:01.940]very weak bonds and that gives rise to
[00:16:04.130]the fact that these sheets can move easily,
[00:16:06.830]relative to each other, so you can use this material
[00:16:09.770]as lubricants, you can use it in pencils, for example.
[00:16:14.172]Carbon atoms make this material.
[00:16:17.500]Now you can the structure, and therefore
[00:16:20.352]you change the coordination of the carbon atoms.
[00:16:24.500]And everything changes, completely, I think
[00:16:27.360]everyone would agree, you would rather have this
[00:16:29.823]than a pile of graphite.
[00:16:32.630]This is suddenly diamond, so if you bring that same,
[00:16:37.210]so to say,
[00:16:39.170]identical
[00:16:40.510]carbon atoms, in a
[00:16:41.750]completely different structure, the
[00:16:44.600]chemistry changes.
[00:16:46.870]For the experts, you go here, from what is called
[00:16:49.677]sp2
[00:16:50.579]hybridization,
[00:16:52.200]all to SP3 hybridization,
[00:16:54.521]over to this.
[00:16:55.354]So it is a change in the electronic structure,
[00:16:57.880]everything changes.
[00:16:58.713]This is a very, very hard material.
[00:17:00.910]It has this stuff, it is black.
[00:17:04.490]This stuff is transparent.
[00:17:06.160]It has a very, very high index of refraction,
[00:17:10.900]that's why diamonds are so shiny,
[00:17:12.610]and people like them.
[00:17:14.240]This stuff is electric deconducting,
[00:17:17.110]this is a white, pen cap, semi-conducting material,
[00:17:22.280]an insolator, basically, so totally different, right?
[00:17:25.757]And here's another, another form,
[00:17:27.158]you probably have heard of it, but
[00:17:29.340]that gave rise to a noble prize, I think,
[00:17:31.510]in 2010, we will see that in a second.
[00:17:34.960]This is graphite.
[00:17:36.206]Because of this weak, fundamental bond here,
[00:17:39.860]you can peel off individual layers from this graphite,
[00:17:44.340]until you end up with, well,
[00:17:46.740]it's hard work, and rarely happens.
[00:17:49.930]But sometimes it does.
[00:17:51.630]And then you end up with an individual sheet
[00:17:54.770]of this type, which is then called graphite.
[00:17:57.770]Which has fascinating properties.
[00:18:00.410]Actually, this is already one of those new quantum material,
[00:18:03.630]if you like.
[00:18:04.710]It is an unbelievable material, so many properties
[00:18:07.690]and possibilities to explore.
[00:18:09.810]The strongest material ever discovered by man.
[00:18:12.695]The electrons in this material behave relativistically.
[00:18:17.230]We call them dirac fermions,
[00:18:19.083]the optical, electrical, mechanical properties,
[00:18:22.724]sever conductivity.
[00:18:24.380]Everything is completely alien and potentially very useful.
[00:18:28.550]And, also, sensitively depends on details
[00:18:32.030]of the etches here on this graphine.
[00:18:35.763]I brought you an example, I'm not sure
[00:18:39.370]this is so much more enlightening,
[00:18:41.423]but here you see a model of graphine.
[00:18:43.743]You see this particular hexagonal structure,
[00:18:47.470]and again that indicates that
[00:18:49.070]this is at a 120 degree angle,
[00:18:51.260]meaning you have this SP2 hybridized.
[00:18:57.970]And then we have another form of carbon,
[00:19:00.900]not shown here, the buckyballs we've all heard of.
[00:19:04.607]But I come back to those a little later, as well.
[00:19:08.280]Okay.
[00:19:09.550]So this, this finding is as simple as it looks like.
[00:19:13.677]It was very significant and gave this Nobel Prize
[00:19:16.320]to these two gentlemen in 2000 and 10.
[00:19:19.690]This guy does other things, also,
[00:19:21.210]he levitates frogs within magnetic fields
[00:19:24.944]and puts his dog on papers, I think like that.
[00:19:29.950]All right.
[00:19:31.530]So let me have one more look into this, this
[00:19:33.860]fundamental stuff, a different look into
[00:19:36.900]the structure-property relationship.
[00:19:39.290]So, the first look was more coming from
[00:19:41.310]the chemistry side, this may be coming a bit more
[00:19:44.520]from the typical physics side.
[00:19:46.380]So, essentially, the same thing.
[00:19:49.010]So this time, we look at it from the
[00:19:51.040]quantum mechanical phenomemon,
[00:19:53.940]that confinement, so
[00:19:57.290]limiting the possibilities
[00:19:58.730]of the electrons to move around in a solar.
[00:20:01.980]Changes everything, in the sense that it
[00:20:05.100]changes the electronic structure.
[00:20:07.397]And when you change the electronic structure,
[00:20:09.690]you change the properties.
[00:20:11.946]Structure, properties.
[00:20:14.260]So, in other words, if you have a
[00:20:15.590]handle on changing these structures, at will,
[00:20:20.000]let's say arranging atoms, at will,
[00:20:22.143]a dream of nanotechnology.
[00:20:24.120]You have full control over the electronic structure,
[00:20:27.410]and if you have control over the electronic structure,
[00:20:30.030]you have control over all properties.
[00:20:32.260]Electrical, mechanical, optical, magnetic, everything.
[00:20:36.770]And what happens if you simply, in the first approach,
[00:20:40.610]confine the motion of electrons.
[00:20:43.820]So we go from three-dimensional objects to
[00:20:46.070]a two-dimensional object, by making it thinner,
[00:20:48.180]to a one-dimensional, then making a wire,
[00:20:50.370]to a zero-dimensional, making it a dot.
[00:20:53.680]And I brought here something,
[00:20:55.040]you may not have seen,
[00:20:56.080]it's a little bit abstract,
[00:20:57.230]but I show it anyways,
[00:20:58.530]because it's so important.
[00:20:59.467]And it's called the density of shapes,
[00:21:01.700]it tells you how many electronic states you can
[00:21:05.430]find at a given energy,
[00:21:06.980]in an interval of energy between e and e-clusters.
[00:21:12.560]And this one here is obviously just a
[00:21:14.650]parabola for the three electrons,
[00:21:17.000]in the back material.
[00:21:19.160]And now you notice,
[00:21:20.260]we don't go into detail but you notice
[00:21:22.130]that if you shrink the dimension
[00:21:25.130]and therefore limit the possibility of
[00:21:27.107]the electrons to explore,
[00:21:28.830]let's say, the z-direction,
[00:21:31.830]that has a profound impact on the
[00:21:34.027]density of electronic states.
[00:21:36.990]Until you get to the zero dimension,
[00:21:38.980]where you just have a small dot,
[00:21:40.930]a nanodot.
[00:21:42.427]And then you see,
[00:21:43.810]you have these three states,
[00:21:46.100]very, very, very similar
[00:21:48.330]to what we know already from the electronic states
[00:21:51.130]and atoms, where you have these
[00:21:52.480]three energetic levels.
[00:21:53.840]This is why we call these things artificial atoms.
[00:21:57.940]And you'll see,
[00:21:58.773]they are very useful, but you'll see that in a minute.
[00:22:00.550]So, again, a profound example that structure
[00:22:05.842]determines the electronic structure,
[00:22:07.670]and that determines all properties.
[00:22:09.990]Not so often, you'll want the other way around, right?
[00:22:12.597]You want to know what electronic structure
[00:22:16.300]do I have to have to have a certain property.
[00:22:19.152]And what structure, in real space of atoms do I have to
[00:22:23.870]generate in order to get this electronic structure.
[00:22:25.990]This is an inverse problem, and very hard, right?
[00:22:29.190]That's why we have theorists, anyone here?
[00:22:32.129]Okay.
[00:22:34.020]Okay, so, let's come back to these zero-dimensional objects.
[00:22:37.963]They are very useful for quantum dots.
[00:22:41.460]And they are useful in multiple ways.
[00:22:43.581]First of all, you can already buy devices at Best Buy,
[00:22:48.030]for something that depend on the physics of quantum dots.
[00:22:53.430]But they are also related to textbook
[00:22:58.061]101
[00:22:59.203]of quantum mechanics, namely the single particle
[00:23:03.600]in a box problem.
[00:23:04.433]What you see here, this is a typical first problem
[00:23:07.670]you encounter when you solve quantum mechanical problems.
[00:23:11.140]One particle in the box, here with
[00:23:13.850]infinite high potential volume.
[00:23:15.903]And you see what you get of this is discreet,
[00:23:18.710]and is sending waves, so that's the wave,
[00:23:21.920]which is typical for quantum mechanics.
[00:23:24.253]What you see here, is that the electrons have
[00:23:26.420]wave properties.
[00:23:27.800]And you see, associated with this particular is
[00:23:30.400]sending waves, so-called ionic energies, ion values.
[00:23:34.830]Discreet energy levels.
[00:23:36.370]So, like you almost have it in an atom.
[00:23:39.080]That means if you can play, let's say,
[00:23:41.850]with the size of those quantum dots, and
[00:23:43.890]typical semi-conductive dots are just have a radius
[00:23:47.441]of between 10 and 15 atoms.
[00:23:50.411]So, if you play with that size,
[00:23:52.112]you play with the energetics, and the
[00:23:54.712]energetic location of these energy's levels.
[00:23:56.992]Particularly, you modify the position of that ground state
[00:24:01.043]and that means you can modify how electronic states
[00:24:06.160]are excited in those quantum well structures.
[00:24:08.851]And how they get so, to say, jump back,
[00:24:13.421]and by doing so in a process of fluorescent light.
[00:24:18.746]Simply by changing the size of those dots,
[00:24:22.259]you change the emitted light.
[00:24:23.947]And I can show you that.
[00:24:25.328]I have, here, a demonstration of
[00:24:28.358]quantum dots solved in a liquid.
[00:24:30.998]And these are semi-conductive quantum dots.
[00:24:34.010]And the only difference between the materials here
[00:24:37.799]and the tubes here is the size of the dots.
[00:24:42.290]And let me show that, by frying those in
[00:24:46.630]ultra-violet light, I will get different florescent light
[00:24:51.420]out of those quantum dots when they have different sizes.
[00:24:54.860]Now, we can see that when I turn off the light,
[00:25:06.444]so this one shines green,
[00:25:07.760]I hope you can see that.
[00:25:10.030]This is yellow.
[00:25:13.080]Orange.
[00:25:15.620]And reddish, right?
[00:25:19.170]And that is directly
[00:25:24.212]related to the radius
[00:25:27.852]of those quantum dots,
[00:25:30.970]with the help
[00:25:31.803]of this
[00:25:33.250]formula you see.
[00:25:34.740]The larger you make the quantum dots,
[00:25:36.855]the lower this energy gets,
[00:25:39.690]and that means the longer the wavelength
[00:25:41.540]of the emitted fluorescent light will become.
[00:25:45.650]Now, what can you do with that?
[00:25:47.070]Well, for example, you can build these
[00:25:51.073]wonderful pure LED displays.
[00:25:55.639]Which have a wonderful, I mean,
[00:25:57.540]you probably have seen them, in the, in the
[00:26:00.804]at Best Buy or otherwise.
[00:26:03.253]So this is a wonderful application of nanotechnology
[00:26:06.440]which uses already these quantum dots,
[00:26:07.918]and they have phenomenal properties.
[00:26:09.987]You can print them, easily, they are flexible,
[00:26:14.161]and the best
[00:26:15.362]is yet to come.
[00:26:16.670]So, currently, in these displays,
[00:26:18.367]they are still excited, pretty much.
[00:26:20.830]And exactly the way I did that was
[00:26:22.910]by having LEDs
[00:26:24.503]of ultraviolet, ultraviolet light
[00:26:27.530]shining on those quantum dots,
[00:26:29.720]and then using the fluorescent light,
[00:26:34.020]but in
[00:26:34.853]the making.
[00:26:36.460]Our process is where you have other means
[00:26:38.610]to electrically stimulate the emission of light
[00:26:41.570]and then you don't need the LEDs anymore.
[00:26:44.180]And then you have a
[00:26:45.013]true quantum
[00:26:47.029]dot TV,
[00:26:48.630]at some point.
[00:26:49.463]Probably in the very near future.
[00:26:51.660]Even better.
[00:26:53.200]Okay, next important property that tells us
[00:26:55.893]that nano is more than just small,
[00:26:59.270]are those, those infamous
[00:27:01.667]emergent interface phenomena.
[00:27:05.310]What does it mean, it pretty means, it's the, the,
[00:27:08.780]old
[00:27:09.751]saying
[00:27:10.680]that the
[00:27:12.513]the, that an object is more than just the
[00:27:15.850]sum of it's part.
[00:27:17.130]And that holds particularly for
[00:27:19.320]such multi-layer structures.
[00:27:21.676]Let's keep it simple, let's say we have just
[00:27:23.970]two different constituents,
[00:27:25.370]material a and material b.
[00:27:26.507]You put them together, and
[00:27:28.910]from back,
[00:27:30.961]you would expect that you get a behavior that
[00:27:34.190]is a mixture,
[00:27:36.026]of a
[00:27:37.070]and b,
[00:27:38.410]right?
[00:27:39.500]They go through, or something like this.
[00:27:42.300]For nano materials, that is no longer the case.
[00:27:45.640]So 'a' plus 'b'
[00:27:47.524]is the properties of this AB
[00:27:50.383]is different from just 'a' plus 'b'.
[00:27:52.707]Why is that?
[00:27:54.400]It's again because there are so many atoms,
[00:27:57.600]sitting at the interface,
[00:27:59.550]that then interact with each other,
[00:28:01.710]and the interaction contribution
[00:28:03.680]at the interface significantly
[00:28:06.110]contributes to the properties
[00:28:07.500]of this overall structure.
[00:28:10.050]You can no longer ignore
[00:28:11.530]what is happening at the interface,
[00:28:13.180]relative to the entire system.
[00:28:15.660]And at the center,
[00:28:16.493]you make the individual constituents,
[00:28:18.956]more important become those interfaces,
[00:28:21.300]and you can make it that they
[00:28:23.036]dominate everything.
[00:28:26.120]This, again, this insight,
[00:28:28.340]and, and the results of it
[00:28:30.033]have been rewarded with a Nobel prize.
[00:28:32.690]There's this famous saying by Herbert Kroemer,
[00:28:35.212]the interface is itself is the interface.
[00:28:38.080]So the interaction today is playing
[00:28:40.760]at the interface, it's the interface that matters.
[00:28:43.553]Here's an example from my own research,
[00:28:46.950]in my own group,
[00:28:48.015]we are interested in putting different materials,
[00:28:51.855]magnetic materials, on top of of each other,
[00:28:54.490]in ultra thin films.
[00:28:56.450]Material 'a', this one here is an antiferromagnetic,
[00:29:00.804]and barely reacts on applied magnetic fields.
[00:29:04.480]So, it brings up a little bit magnetization,
[00:29:07.110]but only if I apply a magnetic field,
[00:29:09.383]like shown in this sketch here.
[00:29:10.240]Material 'b' is a ferromagnetic, and in our case,
[00:29:13.200]it is also a multi-layer,
[00:29:14.770]but it could also just be a ferromagnetic material
[00:29:17.202]commonly used in something like this.
[00:29:18.640]And this has a very profound magnetic crystalletic effect,
[00:29:22.873]lots of magnetization in response
[00:29:24.752]to an applied magnetic field.
[00:29:26.272]And it has this crystal film,
[00:29:28.165]typical feature of the so-called ferromagnetic.
[00:29:31.110]Like the ones you have at your refrigerator.
[00:29:34.460]Now, what happens if you put these two things together
[00:29:37.310]and then change film?
[00:29:38.910]You would, not easily, coming from the microscopic word,
[00:29:42.520]expect a mixture of these two properties.
[00:29:44.880]Literally super imposing, so to say.
[00:29:47.071]That is not what's happening here.
[00:29:49.147]Our data, for exactly that icon system,
[00:29:51.792]and you see the resulting surface
[00:29:54.014]is qualitively, completely different.
[00:29:56.660]It is totally distorted in this sense,
[00:29:59.430]and there are loops that are reminiscent of this,
[00:30:02.592]but shifted to the left and to the right,
[00:30:04.870]we call that a so-called exchange bias effect.
[00:30:07.680]And you can see that this is an interface, in fact,
[00:30:10.963]and emerging interface effect.
[00:30:13.490]If you now crank up the temperature,
[00:30:15.704]and see what happens,
[00:30:17.240]then you see that once this system is
[00:30:19.340]no longer having the property of material a
[00:30:22.280]above the certain critical temperature,
[00:30:24.070]we simply have a temperature like that back.
[00:30:27.130]Okay.
[00:30:28.897]All right, well, I could talk about this more than a day,
[00:30:32.600]but we need to move on.
[00:30:34.130]What else is interesting about the nano,
[00:30:35.820]well, certainly the fact that the
[00:30:37.660]nano gives us a window into the quantum world.
[00:30:40.480]Here is an experiment which is mind-boggling in my mind,
[00:30:44.201]meanwhile it's old, actually.
[00:30:46.610]It is, it is an experiment done by a group
[00:30:50.060]from IBN in
[00:30:51.090]1993.
[00:30:52.618]And I vividly remember when this came out,
[00:30:55.687]and one of these guys, I forgot who it was,
[00:30:58.389]gave a presentation in a theater in Brazil,
[00:31:01.289]a meeting which I attended.
[00:31:03.730]And I couldn't resist, I had to, and I'm
[00:31:06.053]a very shy person, believe it or not, but
[00:31:08.210]I had to go to him and say,
[00:31:10.778]"Really, man? Really?
[00:31:14.520]So, what we see here,
[00:31:16.480]are 48 iron atoms,
[00:31:18.407]which they've put in a controlled way,
[00:31:22.182]on a metallic copper substrate, right?
[00:31:26.370]And they later, they took an image of what they did,
[00:31:28.550]so they used the same instrument,
[00:31:30.360]a so-called scanning, scanning, excuse me.
[00:31:33.796]A scanning, tunneling microscope,
[00:31:36.764]they used it in two ways.
[00:31:38.223]In one way, they used it to put those
[00:31:40.827]48 iron atoms into place
[00:31:42.703]and the other way, they
[00:31:44.140]used it to take that image.
[00:31:45.720]And what you see here, what is so fantastic about this,
[00:31:50.803]are these rippers.
[00:31:53.115]Because these are standing waves of electrons,
[00:31:57.881]so you basically can see, again,
[00:32:00.940]what you would quantum mechanically solve
[00:32:04.506]in a homework exercise, in the particle in a box exercise.
[00:32:08.797]You see these standing waves here,
[00:32:12.110]like you see the standing waves in your
[00:32:14.270]cup of coffee, when you shake it, excited a little bit.
[00:32:17.420]Same thing.
[00:32:18.520]So, you see the electronic waves, and the atoms,
[00:32:20.979]and all that.
[00:32:21.812]Unbelievable.
[00:32:22.972]Also, it is also the, at the time at least,
[00:32:26.920]the example for controlling metal, atoms,
[00:32:31.591]metal by atom.
[00:32:32.424]And by doing with it exactly what you want, right?
[00:32:35.780]So this is unbelievable.
[00:32:37.040]It was 1993, and you can really see the
[00:32:41.510]fundamental laws of nature.
[00:32:42.843]You can look at them, basically.
[00:32:44.830]I think that's remarkable.
[00:32:46.662]Again, this example.
[00:32:48.294]All right, so now I hope you enjoyed that,
[00:32:52.175]but it's hopefully getting more exciting now.
[00:32:55.560]Now we ask, what's, where's a
[00:32:59.175]nano science today?
[00:33:01.155]And how can we fabricate nano structures?
[00:33:05.038]So, the first thing you need are tools, right?
[00:33:08.970]Tools to make these things.
[00:33:11.313]And we here at UNL have these tools.
[00:33:15.600]Literally all of them.
[00:33:17.320]State of the art.
[00:33:19.000]And there are two methods to basically achieve that.
[00:33:22.530]Similar to, let's say,
[00:33:24.023]two approaches, to lead a group, right?
[00:33:28.727]There's this bottom-up approach,
[00:33:32.085]and maybe not-so popular the top-down approach,
[00:33:35.860]but in nano science both are on equal foot.
[00:33:38.750]So let's start with the bottom-up approach.
[00:33:40.710]Here, again, an example from my own group.
[00:33:43.365]Here you see a machine, that is called
[00:33:45.670]the molecular beam, at the epitaxy machine.
[00:33:48.240]A big word.
[00:33:49.073]It basically means that you deposit the
[00:33:51.861]material atoms, or molecules,
[00:33:53.643]in a very controlled way,
[00:33:56.395]on a substrate.
[00:33:57.802]And the way you do that is,
[00:34:00.380]in principle, very simple,
[00:34:01.722]here is a cartoon.
[00:34:02.555]You have a little infusion cell,
[00:34:05.152]a ceramic crucible,
[00:34:06.381]which you fill with the material
[00:34:08.482]you want to deposit.
[00:34:10.350]And, in our case, iron and cobalt,
[00:34:12.250]or nickel, and things like that.
[00:34:14.200]You heat it up, with a good old tungsten wire,
[00:34:18.820]where you drive a high current through
[00:34:20.527]and it gets hot.
[00:34:21.990]And then in that fuel, we have
[00:34:23.620]a very special evaporation process,
[00:34:25.397]where the material comes out as
[00:34:27.500]a beam, and is deposited here in a very controlled way,
[00:34:32.080]almost atom-by-atom, if you'd like,
[00:34:34.096]on the substrate.
[00:34:36.640]And you can achieve remarkably
[00:34:38.426]controlled films through that.
[00:34:41.870]Very similar, the details, the devil is in the details,
[00:34:45.720]is this technique which we have in the
[00:34:48.230]Nebraska Center for Materials,
[00:34:49.063]in nano science, you would call this a pulse,
[00:34:51.900]a laser in position.
[00:34:53.050]In principle, very similar,
[00:34:54.217]but again you want to deposit material
[00:34:56.410]on the substrate,
[00:34:57.310]the substrate is in an ultra-high or at least high vacuum.
[00:35:01.753]The only difference is the way you, you deposit,
[00:35:04.900]you create the material that goes
[00:35:08.290]from the substrate, from the target to the substrate,
[00:35:11.770]here it's done by laser pulses.
[00:35:13.957]And both have pluses and minuses depending on what you do.
[00:35:17.850]There are other methods, here's one more.
[00:35:20.320]Electron beam evaporation,
[00:35:22.600]so you take, you create,
[00:35:23.997]three electrons by heating a filament,
[00:35:26.797]you accelerate them in a voltage,
[00:35:29.226]then you bend them onto your target,
[00:35:32.007]and then the electrons come in with kinetic energy,
[00:35:35.320]heat up the material, and then evaporate the material.
[00:35:38.360]So, very similar.
[00:35:39.760]In all cases, you can do it very well,
[00:35:41.962]and very carefully you can come close
[00:35:44.470]to something like this.
[00:35:46.150]A controlled deposition of the material,
[00:35:48.738]where you have control over the structure,
[00:35:51.579]at least in this direction,
[00:35:53.471]in the direction of the normal film,
[00:35:57.220]you can control layer-by-layer,
[00:35:58.930]what kind of atoms there are,
[00:36:00.660]and how they are arranged.
[00:36:02.480]And that allows you to create an artificial material,
[00:36:06.780]on an atomic level.
[00:36:09.190]And, yeah.
[00:36:12.600]This we have already seen,
[00:36:14.010]another bottom-up approach with the stem from the IBN group,
[00:36:18.220]that is exactly the experiment we have just seen.
[00:36:21.140]And meanwhile, these things are
[00:36:23.280]more or less done again,
[00:36:24.560]we have those here at UNL,
[00:36:26.080]here's an example of similar machines
[00:36:29.433]we have with the materials of
[00:36:31.970]research science and engineering
[00:36:34.100]sent in by a former colleague,
[00:36:35.940]Axel Enders, was an expert also in this field.
[00:36:38.734]And, talking about Axel Enders,
[00:36:40.840]here's an example from an approach
[00:36:43.676]he likes to do, another bottom-up approach,
[00:36:49.000]it's a, if you like, it's a lazy approach.
[00:36:52.080]Well, it's not, but let me call it that.
[00:36:54.510]And let nature do the work for you.
[00:36:57.620]Let nature and meaning, the energetics,
[00:37:00.742]decide where the molecules are
[00:37:03.846]supposed to come at rest positions,
[00:37:07.780]And if you do all of that, very carefully,
[00:37:09.780]you can get very ordered structures here
[00:37:12.080]on the particularly chosen substrates.
[00:37:14.790]So, we saw the bottom-up approaches,
[00:37:17.320]let me briefly talk about top-down approaches.
[00:37:20.570]So, this is just the opposite of bottom-up.
[00:37:23.560]You start from individual atoms, so to say,
[00:37:25.730]which you evaporate, and organize.
[00:37:27.616]Top-down you start from something microscopic,
[00:37:30.480]and pass out the nano structures.
[00:37:32.165]Here's the machine again, one we have
[00:37:34.810]in the Nebraska Center for Materials and Nanoscience,
[00:37:38.075]a line beam etching machine
[00:37:39.885]that allows us to etch by, with ions,
[00:37:44.080]ions that have been accelerated in the presence of
[00:37:47.290]an electric field to high kinetic energies,
[00:37:49.640]then they bump into the target and take off material,
[00:37:55.258]and that allows us to create these type of
[00:37:58.780]structures with very high aspect ratios.
[00:38:01.810]So, when you do things like that,
[00:38:03.320]you always need to have a mask.
[00:38:05.349]And there are in this business,
[00:38:07.707]there are two ways to create a mask.
[00:38:09.540]There's a technique that is known as lithography,
[00:38:12.340]that is the standard technique used today
[00:38:15.338]in a microelectronic semi-conductive industry.
[00:38:18.538]That, to approach this, one is the optical lithography,
[00:38:22.040]the other is the electron-beam lithography.
[00:38:24.110]Again, these are pictures taken from
[00:38:25.750]our centers here at UNL.
[00:38:27.640]So, basically, what you do is,
[00:38:29.309]you have a very far,
[00:38:31.469]spin coat a photopheresis off on it,
[00:38:35.026]and depending on what structures you want to have later,
[00:38:39.555]you have to have a mask,
[00:38:41.259]and then you shine light on this mask,
[00:38:45.027]and then you make an image,
[00:38:48.480]and that image means there are regions
[00:38:50.850]on your photopheresis which are exposed to light
[00:38:53.780]and regions that are not exposed to light.
[00:38:56.360]Both that are exposed to light change, for example,
[00:38:59.057]the polymer hardens,
[00:39:00.346]and then you can etch, for example,
[00:39:04.029]the unexposed part, the way,
[00:39:06.868]or depending on what photopheresis you have,
[00:39:10.064]the etch of an exposed part,
[00:39:11.962]to deposit new materials that you create,
[00:39:14.673]into nano structures.
[00:39:16.230]You can do that with light,
[00:39:17.980]but you can also do that with electrons,
[00:39:20.440]electrons have an example or an advantage
[00:39:23.010]that I come back to in a little bit later.
[00:39:25.330]In general, electrons are quantum particles
[00:39:28.242]and as such, like light,
[00:39:32.690]they have a wave nature.
[00:39:34.170]They have a wave length.
[00:39:35.735]But, the wave lengths of electrons
[00:39:37.740]can be tuned by the momentum of kinetic energy they have.
[00:39:41.863]And you can make the wave length shorter,
[00:39:44.083]then you can make the wave length of light
[00:39:46.170]at the same energy.
[00:39:47.890]And that means you can get better resolution
[00:39:50.110]with electron beam lithography.
[00:39:52.010]Here are examples, again, UNL examples
[00:39:54.623]made some time ago, but still very impressive.
[00:39:57.760]These are Jinsong's junctions arrays,
[00:40:02.978]and these are superconducting arrays,
[00:40:06.940]something similar are very important these days
[00:40:09.400]in the realization of quantum computers,
[00:40:12.329]we'll talk about that in a minute.
[00:40:14.468]And this is an example where such an array
[00:40:16.740]has a typical length of 200 nanometers.
[00:40:20.393]So let me bring back the scale and the comparison.
[00:40:24.090]Here it is.
[00:40:25.240]You remember, for example, the blood cell,
[00:40:29.210]the red blood cell, is somewhere here
[00:40:31.910]on the order of, let's say,
[00:40:35.283]almost a 100 microns.
[00:40:38.649]So something, a red blood cell is something
[00:40:41.980]you can see with an optical microscope.
[00:40:44.190]So, that tells you what Feynman really means
[00:40:46.842]by his vision and his talk.
[00:40:49.350]There's plenty of room at the bottom, there is.
[00:40:52.596]These objects are gigantic compared to what
[00:40:57.810]we can actually fabricate in a controlled manner
[00:41:00.560]in the lab.
[00:41:01.470]So, you can make functional things,
[00:41:03.180]that are tiny compared to the cell.
[00:41:05.210]And maybe you can bring it into the cell,
[00:41:06.510]or attach it to the cell, and so forth.
[00:41:09.220]So, there's lots to do.
[00:41:11.513]Okay, now we have seen
[00:41:15.540]how we can fabricate things,
[00:41:16.900]now let's see how we can look at things.
[00:41:19.010]Characterize them.
[00:41:20.510]And, I told you about the fantastic properties
[00:41:24.494]of electrons, that they have wave properties,
[00:41:27.350]and that I can basically tune the wavelength.
[00:41:29.653]The higher kinetic energy the electron has,
[00:41:32.572]the shorter the wavelength is.
[00:41:35.669]That's a fundamental physics insight,
[00:41:38.409]discovered by Boyle.
[00:41:40.981]And that's why these wavelengths
[00:41:43.330]are called Boyle wavelengths.
[00:41:45.122]That's why electrons microscopy is so much
[00:41:49.760]superior fundamentally, already, over light microscopy.
[00:41:54.638]Because you have shorter wavelengths,
[00:41:57.200]and then, according to our theories about resolution,
[00:42:01.540]these things are far superior in resolution.
[00:42:05.190]This one, again, is from MCMN,
[00:42:07.290]it's a 200 kiloelectron volt microscope.
[00:42:11.360]And I show you, now again, an example from my group
[00:42:13.950]what you can resolve with instrument like this.
[00:42:16.364]This is material that my group has grown, here,
[00:42:20.775]in Nebraska, with the help of so-called
[00:42:23.386]pulsed laser deposition.
[00:42:25.636]The machine we have here.
[00:42:28.690]And what you see here, and this is so remarkable,
[00:42:32.970]are columns of individual atoms.
[00:42:35.453]So, some people make a big deal out of the
[00:42:37.703]"Can you see atoms?"
[00:42:39.030]Yeah, you're wrong.
[00:42:39.863]We can see columns of atoms.
[00:42:42.400]So, we know the structure of material,
[00:42:44.520]it's a particular oxide, called carbon oxide.
[00:42:47.429]The structure looks like this,
[00:42:49.228]and I want to draw your attention to this
[00:42:52.410]buckled structure here of the column's irons.
[00:42:55.400]This buckling, so, if you take it's place on a
[00:42:59.344]substratum level, and this can still
[00:43:03.531]be easily resolved
[00:43:05.829]with more electron molecules, as this
[00:43:07.970]data published here in our manuscript.
[00:43:11.180]Okay, so, what can you do with all of this?
[00:43:13.930]And what is happening today, then hopefully
[00:43:16.520]we still have a little bit of time for the future.
[00:43:18.710]So, let me get started with something exciting.
[00:43:20.660]It's not truly nano, but it's still
[00:43:22.240]exciting and it's on the right path.
[00:43:25.782]The human hair, is over here.
[00:43:28.155]10 to the minus four meters.
[00:43:30.380]And this is called 3D nanoprinting,
[00:43:33.893]this is not yet truly nano,
[00:43:35.789]but still it's printing stuff,
[00:43:37.839]with the highest definition here on a small scale.
[00:43:41.700]So, you see here human hair, and
[00:43:43.767]you see the sculpture of this woman here on the hair.
[00:43:47.768]Then by printing, nano printing, here's this race car
[00:43:51.736]nano printed on a similar scale.
[00:43:54.180]And again, we have 3D printers here at UNL,
[00:43:56.790]not specialized to this.
[00:43:58.370]They're optimized to do other things, but still.
[00:44:01.490]3D printing is nothing strange for us.
[00:44:04.178]Then, let's go way down, and let's go
[00:44:07.321]truly to the nano scale.
[00:44:09.218]This is an image and research done
[00:44:13.970]by a colleague
[00:44:15.612]at Rise University, already, in 2006
[00:44:20.630]he constructed this nanocar.
[00:44:22.500]And the original work that he was interested in,
[00:44:25.260]what he wanted to show is,
[00:44:26.700]you see here these buckyballs,
[00:44:30.080]that are basically acting as tires, right?
[00:44:35.150]And, at the earliest stages, he wanted to know
[00:44:37.780]if I had a car like this, and put it on the substrate,
[00:44:40.259]let's say gold or something, is this thing just
[00:44:44.168]and put it at high temperature, for now,
[00:44:48.300]so that thermal expansion takes place,
[00:44:50.856]is this thing just sliding on the surface,
[00:44:54.048]or are these tires are actually spinning like
[00:44:57.206]they're really spinning like a car?
[00:44:59.920]And it turns out that they can rotate, so
[00:45:02.810]that was a good start.
[00:45:04.160]Later, and earlier, and simultaneously,
[00:45:08.208]people worked on true molecular motors.
[00:45:12.780]So, can you actually have not only a car
[00:45:15.040]but can you propel it in a controlled way?
[00:45:19.507]You can, guess, if the answer to that
[00:45:20.557]is yes, you can get a Nobel prize.
[00:45:23.280]And the Nobel prize came in 2016 for these gentlemen.
[00:45:27.930]And today there are cars, nanocars,
[00:45:30.960]and there are races of nanocars, I hope I can show you one.
[00:45:36.280]Here's one that was.
[00:45:41.250]So, what happened here was the following.
[00:45:42.920]First of all, these, these investigations happened
[00:45:45.442]at very low temperatures, and again,
[00:45:47.202]the images you see are taken by STM.
[00:45:51.116]By scanning tunneling microscopy.
[00:45:53.607]And before they start, they, they find a track,
[00:45:56.988]on the road or silver surface.
[00:46:02.520]And then, they propel it,
[00:46:04.981]the energy comes again from electrons that tunnel from
[00:46:09.080]the tip of an STM into these tiny structures, and you see
[00:46:13.220]this tiny structure is moving and
[00:46:17.021]just thirty hours later and the race was over,
[00:46:18.820]and these guys won the speed record.
[00:46:24.140]That was 2000 and 17, I think.
[00:46:29.900]Okay, so we are also doing stuff
[00:46:32.840]at the nano scale, at this scale here.
[00:46:34.840]Here's, again, an old example
[00:46:36.960]from my colleague Axel Enders.
[00:46:39.006]And here is an example
[00:46:41.033]from the group of David Samuels, is actually siting here,
[00:46:44.874]in the auditorium.
[00:46:47.560]These are nano particles, and again,
[00:46:50.550]you see them here in an image, in the virtual atoms,
[00:46:54.570]and what one can do with nano particles,
[00:46:57.060]in the scaling of five nanometers, like this,
[00:46:59.908]I tell you in a minute.
[00:47:03.920]Before that, let me, let me come to the example
[00:47:07.896]that everyone can relate to.
[00:47:10.230]So, what is nano technology doing for us,
[00:47:13.210]right now in this very moment?
[00:47:15.520]And we all benefit from this,
[00:47:17.390]nothing like this would exist without nano technology.
[00:47:21.440]Because electronics today is no longer microelectronics.
[00:47:25.710]It is truly nano electronics already.
[00:47:27.820]You see that, because it's the result
[00:47:31.570]of most laws everyone knows, so
[00:47:33.807]at the heart of all the electronics we have;
[00:47:37.470]computers, cellphones, you name it,
[00:47:39.800]is this device.
[00:47:41.097]And it's transits all, these days,
[00:47:42.830]specifically a field electron transistor,
[00:47:44.690]or metal-oxide-semiconductor field-effect transistor,
[00:47:48.210]that's what makes, so to say,
[00:47:50.190]the switches and the logic in all of
[00:47:52.170]our computation devices, cell phones and so forth.
[00:47:55.760]Now, what happened is, over many over decades, is that
[00:48:00.429]these devices got smaller and smaller by a particular
[00:48:03.230]factor, these characteristic lengths, get smaller by
[00:48:06.750]a factor of zero point seven every two years.
[00:48:09.550]Now, if you simply do the math,
[00:48:11.459]and apply the same shrinking factor,
[00:48:14.998]in a fixed time interval, you end up with a law like this,
[00:48:19.556]which you can rearrange in an exponential notation.
[00:48:22.810]And you find, indeed, this is an exponential shrinking
[00:48:27.040]of these characteristic length scaling,
[00:48:29.330]and that is one way to express Moore's law.
[00:48:31.996]And here it is plotted, you see this is a logarithmic scale.
[00:48:35.637]You see the enormous progress that has been made,
[00:48:39.170]and this is already an outdated scheme,
[00:48:42.990]I added a few more recent data, which you see here,
[00:48:46.718]hopefully.
[00:48:47.968]That this 40 nano meter knot, and one more time,
[00:48:52.020]let me give you an idea of what that means.
[00:48:53.860]Where we are, already.
[00:48:55.270]14 nano meters of this pitch length.
[00:48:58.510]What does that mean?
[00:49:01.660]Roughly speaking, 60 silicon atoms in a row,
[00:49:04.533]that makes, that makes 40 nanometers.
[00:49:06.950]So, we are already at the limit of what can be done.
[00:49:11.040]So, let me, what, where did this bring us?
[00:49:13.860]Where are we right now?
[00:49:14.940]Look at this.
[00:49:16.210]This is the infamous IVM computer from 1956.
[00:49:21.119]You have this drive of this monster,
[00:49:23.340]this is a big airplane here in the background,
[00:49:26.427]that's hiding there,
[00:49:28.315]and it has a weight of one ton,
[00:49:29.190]and the incredible storage of, don't laugh, five megabyte.
[00:49:33.441]And, now of course, we all have these things here.
[00:49:36.662]And if I just make the unfair comparison,
[00:49:40.073]and focus on data storage, right?
[00:49:43.446]Then already, the cell phone is vastly superior.
[00:49:47.104]It has fifty, two-hundred sixty five gigabytes,
[00:49:51.390]that is fifty-thousand times the data storage of this.
[00:49:55.100]Not even talking about that the actual chip that has
[00:49:59.000]this storage is probably just a few drum, compared
[00:50:03.150]to a million of drums.
[00:50:04.610]So, another factor of a million
[00:50:07.050]we can find in this unbelievable progress.
[00:50:10.116]Now, this will not go on forever.
[00:50:12.737]There are limitations, and we simply try,
[00:50:16.690]some of us at UNL try, make it try to go on
[00:50:21.270]for more time.
[00:50:22.910]And to do that we have to invent new things.
[00:50:24.590]This is our approach, here, of my group
[00:50:27.208]and the materials we call magneto-electric materials.
[00:50:30.790]So I cannot go into details of this here.
[00:50:33.650]Let me come back to those nano particles.
[00:50:36.100]What can you do with those?
[00:50:37.240]You have just seen pictures from
[00:50:39.180]those fabricated here at UNL.
[00:50:40.470]There are very useful in medicine, for example.
[00:50:43.533]We have already learned that we can
[00:50:46.070]functionalize nano particles, we can make sure
[00:50:48.183]that they're on the surface of particular molecules,
[00:50:50.923]those molecules, then in turn, can attach to cells.
[00:50:54.690]Let's assume this cell is a cancer cell,
[00:50:57.303]then you can have two, two tools, you can either
[00:51:01.140]try to get a medicine, so to say,
[00:51:04.605]inside the cell.
[00:51:05.693]Or, you can apply an approach which is called hypothermia.
[00:51:10.314]It works like this.
[00:51:12.690]It turns out that cancer cells are more
[00:51:14.680]susceptible and die more easily when you
[00:51:17.860]exposed them to heat, than ordinary cells do.
[00:51:21.013]So, how do I bring heat close to the surface?
[00:51:24.210]Well, first of all, I attach this magnetic particle
[00:51:27.041]to the cancer cell, and then from the outside,
[00:51:30.471]I apply a magnetic field, and because there is
[00:51:33.741]magnetic resistance, every time I switch
[00:51:36.470]the magnetization of this cobalt particle,
[00:51:38.373]from one orientation to the other,
[00:51:40.613]I do work.
[00:51:42.054]Work can be twenty-five by the integral
[00:51:44.615]MDA, HDM, or geometrically is given
[00:51:48.992]by the area under this curve, right?
[00:51:52.117]And this work is converted completely
[00:51:54.829]into heat, and if you do it over and over again
[00:51:58.292]then you increase the temperature near the cell
[00:52:01.990]and you can hope that the cell dies.
[00:52:04.930]This is unfortunately not, not there yet,
[00:52:07.179]in the sense that it is approved.
[00:52:08.890]But the pathway is clear, and it's very, very promising.
[00:52:12.390]Another thing very useful, metamaterials,
[00:52:15.061]these are structures where you, I mean obviously,
[00:52:19.651]easily can make structures of material on a
[00:52:22.963]sub-wave length of light.
[00:52:25.959]And if you do that, this becomes, so to say,
[00:52:29.008]an effective medium.
[00:52:30.380]The light doesn't, has a long wavelength,
[00:52:32.530]much longer than this corregation.
[00:52:34.460]It doesn't notice this, but notices
[00:52:36.072]that the diagram and properties have changed.
[00:52:38.950]And you can do fantastic things, with something
[00:52:41.810]that hopefully gets you excited.
[00:52:43.370]Something like cloaking.
[00:52:44.691]Here's an example, where you see cloaking in action.
[00:52:47.520]This is an ordinary object where
[00:52:49.192]an electromagnetic plains wave comes in,
[00:52:51.520]gets scattered, you see the rip that's here,
[00:52:54.552]so when you stand here, because there's this
[00:52:57.870]scattering, you can see that there was an object here.
[00:53:01.360]Here, the electromagnetic wave comes in,
[00:53:03.509]it's a little bit distorted here, but if you stand here,
[00:53:06.670]in the far field, there's still a plain wave.
[00:53:09.181]You can tell, that something was here.
[00:53:11.430]That's cloaking, right?
[00:53:12.610]And that can be done already,
[00:53:14.480]but you cannot do it yet, to the
[00:53:16.180]full spectrum of visible light.
[00:53:17.901]Well, at least we do not know if it can be done yet,
[00:53:20.670]to it's full spectrum.
[00:53:21.860]You can build super-lenses, that can surpass
[00:53:24.509]the diffraction limit on their lenses, so far.
[00:53:28.960]This, again, is an example from
[00:53:30.570]the University of Nebraska, here from the
[00:53:32.764]electrical engineering room.
[00:53:35.060]They built this nano forest, of, of,
[00:53:38.820]of these little sticks,
[00:53:41.969]like multi, different materials.
[00:53:43.983]And it is, again, tailoring multiple optical properties
[00:53:46.811]of these materials.
[00:53:48.870]Another example of the structure on the nano scale
[00:53:51.670]comes from chemistry here, an example
[00:53:53.920]from the Shavinsky group, a fantastic seminar.
[00:53:56.942]This is, again, using the wonder material graphine,
[00:54:01.430]in a particular shape,
[00:54:05.469]and this is a stencil
[00:54:09.371]that, in a particular sense, ultimately cause conductivity
[00:54:13.460]of graphine that dramatically changes when molecules come to
[00:54:17.678]it's surface, that's not the right word,
[00:54:21.830]it's only that what came out.
[00:54:24.160]All right, so I guess as always,
[00:54:26.860]I'm talking way too much.
[00:54:28.253]I'm trying to keep it short, but now comes
[00:54:31.390]hopefully even more exciting stuff,
[00:54:32.880]in the sense that what's next, right?
[00:54:35.130]So I want to look a little bit into the future.
[00:54:37.905]Before we go really into the future, let me go,
[00:54:40.526]let me go into the past, very briefly.
[00:54:44.745]All technologies depends on materials,
[00:54:48.790]and would also, in that can be easily shown.
[00:54:51.854]And our progress of technology will therefore
[00:54:55.950]also depend on progress in material sciences.
[00:54:59.950]And, let, what do I mean by that?
[00:55:01.630]Let's really start from scratch.
[00:55:04.160]If you have the good flintstone,
[00:55:07.130]you could, can make these devices.
[00:55:10.240]You can kill animals, you have meat, meat is protein.
[00:55:14.207]You grow stronger, and you can afford
[00:55:17.040]to have a bigger brain.
[00:55:18.530]That's good.
[00:55:19.457]And, well, sorry for the visuals here.
[00:55:22.189]I'm not saying that you don't have a big brain, but,
[00:55:24.767]now we have other ways to do that.
[00:55:26.650]But that certainly helped the evolution, and,
[00:55:30.039]and from there we went into the bronze age, metrology,
[00:55:34.470]you can built copper and tin allose,
[00:55:39.365]and make a first, useful allose from it here.
[00:55:44.282]Here's a mirror, from the Egypt,
[00:55:48.113]old Egypt area,
[00:55:50.350]and then of course a big step towards the iron age,
[00:55:53.820]and you make tools, and you make superior weapons,
[00:55:57.211]and you conquer, and all that, right?
[00:56:00.379]And then, you make steel.
[00:56:03.140]And with the power of steel you can
[00:56:05.540]suddenly make buildings, and structures,
[00:56:08.177]you can only dream of like this type of suspense,
[00:56:11.770]suspension, bridges, and now today we are in probably
[00:56:16.340]what can be classified as the silicon era.
[00:56:19.264]We are the the homoinfomaticus, if you like.
[00:56:24.590]It's all about information.
[00:56:26.470]We are in the information age.
[00:56:28.930]And this is a graph I took from one of my
[00:56:33.392]favorite future tellers, if you like,
[00:56:38.013]Ray Kurzweil, he's a, I like him a lot.
[00:56:41.778]Because, not just because he is
[00:56:43.898]not just mumbling stuff about the future.
[00:56:47.515]He has a record of major scientific achievements,
[00:56:50.506]among those, the Kurzweil piano which he
[00:56:54.330]made for Stevie Wonder, which I also like a lot.
[00:56:57.370]So he is really good, and he makes predictions,
[00:56:59.824]basically by extrapolating Wirth's law.
[00:57:02.810]And you have seen all of these things,
[00:57:04.670]and his wonderful, intriguing predictions,
[00:57:07.614]but whether you believe or not is a different question.
[00:57:11.003]It's a question whether you believe
[00:57:12.220]in the continuation of accelerated return,
[00:57:14.942]in the form of Wirth's law.
[00:57:16.723]But here, what is the take home message of this graph,
[00:57:20.712]is the fact that we always underestimate exponential growth.
[00:57:25.224]So, if you look, and say today
[00:57:27.520]my computer can maybe simulate
[00:57:29.198]the mouse, the brain of the mouse,
[00:57:32.777]you say, okay, well, what an achievement, right?
[00:57:35.980]And, twenty years earlier, it could maybe
[00:57:38.370]simulate the brain of an insect.
[00:57:40.640]Well, the same time, if Wirth's law keeps going,
[00:57:44.020]it will take to simulate the brain of a human,
[00:57:48.180]and you know, we have already AI
[00:57:50.654]that is very impressive, forgoing these things,
[00:57:53.800]already very impressive, right?
[00:57:55.200]But what is the unbelievable thing, and that's
[00:57:58.940]where the term of the technological similarities
[00:58:01.570]is related to that,
[00:58:04.990]if that would go on like this,
[00:58:06.903]in an exponential fashion,
[00:58:09.091]then the time it takes between achieving
[00:58:13.777]the power of one human brain, and
[00:58:16.057]achieving a computer that has the
[00:58:18.018]computational power of all human brains combined,
[00:58:21.599]is exactly the same span, right?
[00:58:23.499]Whether that will happen or not depends on, well,
[00:58:27.742]on whether Wirth's law goes on.
[00:58:30.956]But we can ask, certainly, another question.
[00:58:34.280]Material science merged into nano material science,
[00:58:37.666]and we can ask what's next, right?
[00:58:39.836]What comes next.
[00:58:40.687]And I would argue, and many of my colleagues probably too,
[00:58:45.810]that the next big thing is quantum materials.
[00:58:48.027]I'd say if you were about that, really just a few,
[00:58:50.516]so let me start with the observation,
[00:58:53.386]if you share that, I think we're already on the same page,
[00:58:57.796]that everything in nature is fundamentally quantum,
[00:59:01.070]because quantum physics, and quantum mechanics, is
[00:59:04.366]the foundation, the fundamental law.
[00:59:06.487]So everything is quantum.
[00:59:08.170]So then you can ask, what is particularly quantum
[00:59:10.340]of all quantum materials, if anything is quantum?
[00:59:12.818]To answer that, we have to go back a little bit,
[00:59:15.916]into the starting points of the first quantum revolution,
[00:59:20.287]which these gentlemen, and of course many others, started.
[00:59:24.780]But these are particularly important in the field
[00:59:27.120]of quantum metaphysics.
[00:59:29.746]And here you see, particularly, what's happening next.
[00:59:33.127]So, electrons are quantum particles, and we need to
[00:59:36.476]describe the materials we use today.
[00:59:39.680]But it turns out, that in solids, one in principle
[00:59:42.927]would expect if I have so many electrons,
[00:59:45.825]let's say, I've got multiples of a multiple number,
[00:59:49.810]10 to the power of 23, all over, right?
[00:59:52.116]So many electrons, that all interact through
[00:59:54.868]a cooling action, with each other, and
[00:59:57.388]they if are quantum particles, I would end up
[01:00:00.040]with a hopelessly complicated problem.
[01:00:02.070]And that is exactly not the case, in most cases.
[01:00:04.960]In most cases.
[01:00:06.196]It turns out, it's a rather straightforward problem,
[01:00:08.130]the electrons behave more or less like three particles.
[01:00:11.090]What does that mean?
[01:00:11.923]Let's first look at the three, classical particle.
[01:00:14.487]All I need to say about it, that if it it's moving around
[01:00:17.316]it has certain kinetic energy.
[01:00:18.810]Because we have all seen this one,
[01:00:20.996]non-classical one, one half in the square,
[01:00:23.850]I can express it in terms of it's momentum,
[01:00:26.640]three square over to M, and I can plot that
[01:00:28.846]as a functional momentum of this, well,
[01:00:31.087]you get it while graphing functional form.
[01:00:33.824]Now, if I want to bring in quantum mechanics,
[01:00:36.440]for this three particles, roughly speaking
[01:00:38.950]all I have to do is apply the Boyle relation,
[01:00:42.180]so I plot in P and it's constant over the wavelength
[01:00:45.870]of the particle.
[01:00:46.876]I can express it with the help of the wave number,
[01:00:50.218]to pi over the number, and again,
[01:00:51.986]I get a functional form that expresses the energy
[01:00:56.470]as the function of this quantum number k.
[01:00:59.526]It's a quadratic relation.
[01:01:01.147]Now, the fascinating thing is, the unexpected thing is,
[01:01:05.720]actually, that if you take now these three quantum particles
[01:01:09.990]and put them into a solid, not much is changing.
[01:01:13.489]You get what is known as the dense structure of solids,
[01:01:17.238]that looks like this, and notice you still see here this
[01:01:21.800]parabola in action.
[01:01:23.980]The only thing that changes is the peracidity
[01:01:27.480]of potential, you get these regions of forbidden energy,
[01:01:31.973]and you get therefore what is known
[01:01:34.800]as the ben's structure of solids.
[01:01:36.733]Now, this explains pretty much everything
[01:01:39.340]which gives rise to the marvels we have today.
[01:01:41.832]These, these coming, new fantastic exo scales,
[01:01:45.773]and super computers, like our cell phones, lasers,
[01:01:49.461]even conventional superconductivity that gives
[01:01:53.680]rise to applications such as MRI, can all be traced back to
[01:01:58.190]this first quantum revolution, if you like.
[01:02:01.471]If there's a first one, there should be a second one, right?
[01:02:04.240]So what's the second one?
[01:02:05.810]Well, the second one, to one extent,
[01:02:08.490]deals with materials that cannot be described
[01:02:11.480]by the quasi-electrons.
[01:02:13.113]So, the motion of an electron,
[01:02:15.641]depends on where all the others are.
[01:02:18.784]That makes it a truly, very complicated, correlated problem,
[01:02:24.356]difficult to predict.
[01:02:26.340]That's a disadvantage.
[01:02:27.430]On the other hand, you get all these new phenomenas,
[01:02:29.787]so-called emergent, you've heard this word before,
[01:02:32.848]emergent phenomena that you cannot
[01:02:34.625]easily predict from interactions with nearest neighbors.
[01:02:40.209]What are those?
[01:02:41.284]Well, most prominently are the high TC.
[01:02:44.430]So, superconductivity, at very high temperatures,
[01:02:47.710]let's say liquid nitrogen, for example.
[01:02:49.877]Very useful.
[01:02:50.877]Heavy fermions, when in a crude approximation,
[01:02:53.909]you can still apply this three particle picture,
[01:02:58.030]but your effective electron mass is ridiculously high.
[01:03:01.459]Thousands of times the mass of an actual, three electron.
[01:03:06.090]So, something strange is certainly going on.
[01:03:09.648]Oxides and nano structures you fabricate
[01:03:12.419]with oxides are materials in that fall
[01:03:14.749]into this class.
[01:03:16.290]All kinds of properties,
[01:03:17.629]two dimensional electron masses form the interfaces,
[01:03:21.269]suddenly different types of ferroic orders pop up;
[01:03:25.027]ferromagnetism, ferroelectricity, that can couple,
[01:03:28.310]that can make multiple materials, you can have
[01:03:31.520]materials that by small changes of external nominators,
[01:03:35.286]turn from a metal into an insulator, that can
[01:03:38.690]be very useful, and things like this.
[01:03:41.387]So, a whole zoo of ferromagnets.
[01:03:44.720]Among the emergent ferrominates, is another
[01:03:47.577]subject that falls into this category,
[01:03:50.050]that is at the so-called topological stage,
[01:03:53.189]it's of metal.
[01:03:54.557]Topological stages of metals have
[01:03:57.250]made it, actually, into mainstream,
[01:03:59.550]anyone have seen this, the Big Bang episode
[01:04:03.740]where Sheldon was talking about topological states,
[01:04:07.830]and he asked in the class, is anyone familiar
[01:04:10.300]with topological insulators?
[01:04:12.090]And they all said yes, and he said
[01:04:13.990]don't kid yourself right now.
[01:04:15.698]Well, but anyways, this is a very, very,
[01:04:19.250]fashionable subject.
[01:04:20.540]What's going on here?
[01:04:22.149]Topological insulators are fascinating
[01:04:24.120]in the following sense; these are
[01:04:26.020]materials that are in the back insulators,
[01:04:29.520]but have, have surface states that
[01:04:33.729]give rise to conduction, as shown here in green.
[01:04:37.312]And there's an additional property,
[01:04:39.511]that is called spin-momentum locking,
[01:04:42.450]so that the magnetic moment of the electrons
[01:04:45.510]and the motion are connected, intimately connected.
[01:04:50.237]So, it has situations, then
[01:04:51.650]where you have surface currents which
[01:04:54.010]run in one direction, where the magnetic moment
[01:04:56.560]points up off of the electrons,
[01:04:57.880]and they run in the opposite direction where
[01:04:59.480]the magnetic moment point stops.
[01:05:01.760]And these, these states are protected,
[01:05:05.453]the keyword is topological protection, by symmetry,
[01:05:09.530]in this case time and emergent symmetry,
[01:05:11.890]so as scattering cannot easily take place from
[01:05:15.247]the spin up to the spin down,
[01:05:16.930]so you cannot scatter an electron that is moving
[01:05:19.810]in one direction, into a state so that the direction
[01:05:23.583]of motion is reversed.
[01:05:26.050]So that's a topologically protected state.
[01:05:28.650]Similar topologically protected state,
[01:05:31.320]I show you now, again, an example from Dave Samuel's group,
[01:05:34.760]this is a topological protected state, in magnetism,
[01:05:38.571]it's a so-called skrymian,
[01:05:40.330]and you see that the structures here
[01:05:42.520]of the atomic magnetic moments
[01:05:44.262]in this particular curled-up way,
[01:05:49.350]and what makes it topological
[01:05:51.051]is the fact that there is no easy way
[01:05:53.601]by continues the formation of the structures
[01:05:56.639]to unwind this, so these guys are very stable,
[01:06:00.782]they are topologically protected.
[01:06:03.697]Dave and company made it so that these can
[01:06:07.695]be made very small, and you can use them for data storage.
[01:06:11.356]You can actually move them around, with electric fields,
[01:06:14.430]and fascinating things.
[01:06:16.360]All right, now I am coming hopefully to my end, right?
[01:06:19.550]So, let me give you the last ideas here,
[01:06:22.415]the look into the future.
[01:06:25.143]So, what's really next?
[01:06:26.654]Well, there's an old saying, whether it's really funny,
[01:06:29.934]why I'm not sure, but you've heard it before.
[01:06:32.220]Prediction is very difficult, especially about the future.
[01:06:35.951]A few things we can say.
[01:06:37.978]So we have now, the advent of quantum materials,
[01:06:42.523]and with that will certainly come quantum technologies.
[01:06:45.450]And there are already existing quantum technologies.
[01:06:49.050]Typically, we don't call it that,
[01:06:50.990]but they exist already.
[01:06:52.151]What can we expect when quantum technologies come?
[01:06:55.912]Well, discoveries with new drugs,
[01:06:58.739]we can, always, probably use those.
[01:07:03.250]Talking about recent events, catalysts,
[01:07:05.699]very important in chemistry, and new types of materials.
[01:07:11.620]And again, the basic idea here, goes back to
[01:07:14.560]Richard Feynman, who pointed out kind of the obvious.
[01:07:18.342]Nature is fundamentally quantum mechanic.
[01:07:22.104]So, if you want to simulate something that is
[01:07:26.970]quantum mechanical in nature, why the heck would you
[01:07:29.380]use something that is classical?
[01:07:31.640]Don't use a classical computer,
[01:07:33.190]use a quantum mechanical computer that does these,
[01:07:36.201]take cares of these particular quantum properties.
[01:07:40.200]So, Richard Feynman envisioned this, and now-a-days
[01:07:42.680]these things become a realization.
[01:07:44.980]Quantum simulators, and more general versions
[01:07:48.230]of quantum simulators, so-called quantum computers.
[01:07:51.870]So, what they both have in common is
[01:07:53.695]that they do not operate with, with classical
[01:07:57.390]yes or no, up-or-down, zero or one bits,
[01:08:02.369]but they operate with linear, super provisional flow states,
[01:08:07.220]which are called quantum bits, or qubits for short.
[01:08:10.668]And together, with this property, which is,
[01:08:12.996]if you want to simplify it, is simply a consequence
[01:08:16.600]of the fact that the underlying quantum mechanical equation
[01:08:20.310]is a linear differentiational equations, so the
[01:08:23.299]super provision principle will hold simply mathematically.
[01:08:27.820]This together, with the fact that there
[01:08:31.030]is quantum entanglement, creates
[01:08:34.370]a vast superiority of quantum mechanical computers,
[01:08:38.110]potentially because we have these
[01:08:40.140]quantum paralleling computing properties.
[01:08:42.780]So now, what has been done is that
[01:08:45.260]these things have already been realized, so
[01:08:47.610]you can trap ions, for example,
[01:08:50.315]in a particular trap,
[01:08:51.827]and then you can fine tune the interaction
[01:08:55.040]between these quantum objects,
[01:08:56.570]and by doing so you can simulate models,
[01:09:00.530]which you would, which a theorist would,
[01:09:02.422]write down as a Hamiltonian, you can map
[01:09:04.744]that Hamiltonian onto these fine-tuned interactions,
[01:09:10.060]and then let the system evolve,
[01:09:14.270]for example, into these ground states.
[01:09:16.080]So, you get the solution.
[01:09:17.130]You get the ground state solution, that's very useful.
[01:09:19.680]And, then of course, all of you have heard about this
[01:09:22.235]recent achievement from Google, they claimed
[01:09:26.784]finally they have, for the first time,
[01:09:29.224]created a quantum supremacy,
[01:09:31.087]meaning that they created a quantum computer,
[01:09:35.430]in this case, a quantum computer of
[01:09:37.390]fifty-three functioning qubits, which are,
[01:09:40.501]superconducting qubits,
[01:09:42.501]which they let operate in this particular shift.
[01:09:47.100]Of course, all of this has to take place
[01:09:48.750]at very low temperatures, very completely useless,
[01:09:52.577]I must say, a problem they addressed,
[01:09:55.357]they could show that this problem can be solved
[01:10:00.214]incredibly much faster than a
[01:10:05.200]classical computer could do that.
[01:10:06.620]So they claim that the classical computer
[01:10:08.880]would take 10 thousand years, but they calculate it in,
[01:10:11.433]I don't know, a few minutes or so.
[01:10:13.200]You can read the details here.
[01:10:15.574]All right, what else?
[01:10:17.880]We don't have to have quantum computers.
[01:10:19.570]We can just go to quantum sensors,
[01:10:21.508]and use the weakness one, the conceptual weakness one,
[01:10:26.318]of quantum systems, and make it into a strength.
[01:10:29.930]So, the weakness one, could say, it's deference
[01:10:32.530]and things like that.
[01:10:33.363]So, quantum mechanics are very sensitive
[01:10:35.398]to external reverberations, but you
[01:10:37.340]can turn it around and make the sensitivity
[01:10:39.360]to external stimulants,
[01:10:40.697]and make it into an extreme sensitivity.
[01:10:43.847]And there are, already, examples for that.
[01:10:47.057]People typically don't call it a quantum device,
[01:10:51.260]but there are.
[01:10:52.093]Here's the one we talked about a lot already,
[01:10:53.940]the scanning-tunneling-microscope uses the fact that
[01:10:57.980]the tunneling, which is a pure, quantum mechanical effect,
[01:11:00.880]the tunneling current between the tip and the substrate,
[01:11:04.710]the one that you look at, depends exponentially
[01:11:07.950]sensitive on the distance between
[01:11:09.966]the tip and the metal surface.
[01:11:12.196]So, this is a quantum mechanical tunneling effect
[01:11:15.154]that is used here.
[01:11:16.144]The same effect can be used to make pressure sensors,
[01:11:20.076]like this, so you have particles immersed that stay
[01:11:25.050]in a polymer, if you bring them closer together,
[01:11:27.406]electrons can tunnel from one particle to the other.
[01:11:29.993]So, the systems becomes conducting,
[01:11:32.610]or if you release the stress, it becomes an
[01:11:34.636]insulating pressure sensor, that uses quantum properties.
[01:11:40.265]Another example, again, a device that you find here
[01:11:43.980]in our center, is a superconducting
[01:11:47.110]quantum interference device.
[01:11:48.800]It uses superconductivity, the microscopic
[01:11:52.006]quantum effect, I would say, to make
[01:11:54.556]ultra-sensitive measurements of magnetization.
[01:11:58.090]And, something we envision, hopefully we can realize
[01:12:00.840]that in something we do, the framework of quantum
[01:12:04.040]materials here at UNL , well, I hope so in the future,
[01:12:06.985]are these nitrogen vacancies.
[01:12:09.526]These are nitrogen atoms that are placed specifically
[01:12:13.625]into a diamond lattice, and the combination
[01:12:18.222]between the nitrogen and the absence of carbon, of carbon
[01:12:22.323]will create a spin state that is extremely sensitive
[01:12:26.415]to external feeders.
[01:12:27.946]And now you can take this, and combine it with this,
[01:12:31.055]and get magnetometers, that are extremely sensitive
[01:12:34.554]and can investigate the magnetic surfaces of samples,
[01:12:38.415]for example.
[01:12:39.830]All right.
[01:12:41.656]I guess I come very close to my end,
[01:12:46.490]so we see really that we can do things that
[01:12:48.686]come close to Feynman's dream.
[01:12:52.116]One of his dreams was this so-called swallowing the doctor.
[01:12:56.280]We are not there yet.
[01:12:57.670]Meaning, building machines that are intelligent
[01:13:00.510]enough to repair and fix issues within our bodies,
[01:13:03.908]but you have seen is that we can make functioning
[01:13:08.894]and significantly complex machinery,
[01:13:14.043]and objects on the nano scale, and those
[01:13:17.360]on the nano scale, is really, really,
[01:13:20.430]way, way, way below the
[01:13:22.775]size of these red blood cells here.
[01:13:25.950]So, there is plenty of room at the bottom.
[01:13:28.600]It's just a matter of time.
[01:13:30.800]Then we have this fantastic new materials, with properties
[01:13:34.230]we haven't really fully explored yet.
[01:13:35.830]There's one idea that is floating around for a long time,
[01:13:39.083]and that's the space elevator, you don't need
[01:13:41.300]chemical rockets anymore to shoot stuff up into space.
[01:13:44.385]Whether it can be done or not is still up for debate,
[01:13:47.320]but there's a lot of things to come simply from the
[01:13:49.600]mechanical properties of this graphine.
[01:13:52.443]And there are the fascinating problems.
[01:13:55.043]Every problem, from fusion reactors, to interstellar flight,
[01:13:59.374]of small, of small starships, ultimately,
[01:14:03.090]depends on materials, period.
[01:14:05.854]So we don't have, yet, the materials to make such
[01:14:08.183]sails, but if we were to have, it's actually feasible
[01:14:10.475]to have small spaceships that could reach speeds of
[01:14:15.363]the fraction of the speed of light, in which
[01:14:18.835]can create a space tower in fifteen years or so.
[01:14:22.490]So, then it's not just quantum computing where
[01:14:25.640]progress is made.
[01:14:26.843]There is the so-called brain-inspired computing
[01:14:29.694]we can create now, artificial accents and neurons
[01:14:33.930]connect them and bring, bring a neuromorphic computing
[01:14:39.015]networks to a point which is way beyond what has
[01:14:43.350]been done by Boeing, where all these things are
[01:14:46.880]still simulated.
[01:14:48.052]If you implement them in hardware, oh boy.
[01:14:50.815]All right.
[01:14:51.900]So, now, let me conclude, and you may wonder why
[01:14:56.377]this is my outlook.
[01:14:57.727]That's only one reason why I put this guy on here.
[01:15:01.537]So that I can say, with my German accent,
[01:15:06.290]I'll be back.
[01:15:07.407]Which I will have made something, right?
[01:15:09.938]That's the only reason, and let me, it all goes like this.
[01:15:14.258]So, we certainly made, made major progress in nano science.
[01:15:18.698]We have these functional systems.
[01:15:20.860]We get closer and closer.
[01:15:22.236]We have new types of quantum materials, that
[01:15:25.218]open the door to quantum information, and
[01:15:29.388]we also have other possibilities that bring us closer
[01:15:33.710]to the internet of thing, the next big thing,
[01:15:35.730]probably brain-inspired computing.
[01:15:37.799]Nano electronics, which we already all carry around with us,
[01:15:41.656]an aspect, another aspect, I haven't even touched,
[01:15:45.426]is the attempt to make nano materials,
[01:15:50.237]nano objects,
[01:15:51.070]more like living things.
[01:15:54.070]For example, self-healing, and self repair,
[01:15:57.357]is a big key word, and polymers, that have this
[01:16:02.107]encapsulated chemicals in it, which heal themselves,
[01:16:05.610]if you cut them exist already, but we even
[01:16:07.928]want to go further.
[01:16:09.758]Self-replication is a necessity, if you want to
[01:16:14.699]fabricate something microscopic, you have to have
[01:16:18.610]nano structures that can replicate, then
[01:16:21.560]take material and combine it to make something big
[01:16:26.332]and microscopic, right?
[01:16:28.308]That's, with the nanomotors, Nobel prize 2016,
[01:16:33.644]and these things, there's a way, there's a way,
[01:16:37.400]so that you have engines that can grab material and
[01:16:40.610]bring it together in a meaningful manner.
[01:16:42.960]Also, there's now very up-to-date, has helped
[01:16:46.380]from biology, you may have heard of it, microbots.
[01:16:48.867]They are not happening on the nano scale, they are on
[01:16:52.490]the scale of cells, but it goes all together.
[01:16:57.550]And that's my last message here.
[01:16:59.780]Don't look at these things as individual achievements.
[01:17:03.070]One can do this, one can do this, one can do this.
[01:17:05.853]This will all come together, and,
[01:17:08.310]and the accelerated return will happen
[01:17:12.520]because it comes together, and then we go somewhere,
[01:17:15.851]into some state, in which I don't know what that is,
[01:17:19.337]but I hope it's a good one.
[01:17:21.350]Okay, with that, I really stop.
[01:17:22.750]I'm probably way beyond my time, as always,
[01:17:25.670]so let me thank you.
[01:17:27.060]If you like, are a grad student, or want to become one,
[01:17:30.010]or even if you are an undergrad, consider to do
[01:17:33.590]nano science, and then, then call me.
[01:17:35.830]Or something like this.
[01:17:37.670]Or get in touch with us, so there are opportunities
[01:17:40.840]to do something like this here, at UNL right now.
[01:17:44.183]All right, with that, let me thank you.
[01:17:46.459](Audience clapping)
[01:17:58.726]Are there any questions?
[01:18:04.975]All right, with that, thank you so much for coming.
[01:18:07.062]Have a good day.

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The Rise of Nanotechnology | CAS Inquire

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