 introduction and thanks everyone for coming. So like you said, I'm Barbara Echner, I'm here at the TU Munich researcher on the body prefab fellowship and I want to show you today how we can record movies on the atomic scale. So I'm sure you are all aware that everything is made out of atoms. That's what we learn in school. So we have the air around us, our own bodies, everything is made out of atoms. But what's more, everything is always in motion. Now, of course, a gas atmosphere, that's fairly easy to imagine. So you have gas that's not very dense and everything is moving around. Even in a liquid, it's still quite obvious that things are moving, that there's order and so on. But I want to also tell you that even in a solid, so everything around you, trees, metals, molecules and atoms are constantly in motion. There's vibrational motion, so the motion of atoms in a rigid arrangement around their positions. But that's also chemical reactions happening, which means there's one formation, one breaking going on. And so one thing that you could see in everyday life is the oxidation of surfaces. So if you have something made out of steel, it can get oxidized, especially if it's in a humid environment or if it's exposed to a solid water and so on. And that's what you would see as thrust. But it also means that this surface of the solid is now chemically transformed. And these chemical reactions, they are important in everyday life, but also in many technical processes. And what I'm trying to do is to understand on a fundamental level what drives the dynamics and chemistry on surfaces, on a solid material. And I want to not just understand them indirectly, I want to really visualize them and look at them. The difficulty is that an atom is very small. Now an atom is typically said to be on the order of less than a nanometer. A nanometer is a billionth of a meter. But I'm sure even then you still can't really imagine how small it is. So I'll make a little scale here. This is a logarithm scale of the length space that we have. So every tick is a factor of 10 smaller. So we start up here with kilometers. Kilometers are really measured distances in if you travel like power, heights of tall mountains and so on. Meters are more everyday objects. You have trees, or you can even measure all the on-size meters. And we can still of course see things in centimeters scale and even just below the nanometer the human eye can still see. So we might be able to make out some structure on a leaf of a tree. But it now gets to the point where a microscope is necessary to really resolve structures well. So we have of course the optical microscope. And the optical microscope is useful in this range here. So down to below the micrometer. So this is 10 to the minus 6. So we can really look at bacteria for example. We can have microscopes for looking at human cells and so on. But the problem is there's a physical limit. This line here is not arbitrary. This is actually an absolute limit to where the optical microscope with light can go. And that's because the wavelength of visibly light is limited. At least this error here is the 300 nanometer is the physical limit where microscopy ends with the optical light. Many technologies exist to try and push to the smaller scale and really look at atoms. I'm currently present just one to the age because there are too many different options. And the one that I'm presenting is the scanning-turning microscope, which is the microscope that I use in my lab every day. So the scanning-turning microscope really shows us things on the nanometer scale. So we can look at molecules. We usually don't even look at big molecules like the steamoglobin, but we instead look at things like smaller molecules like carbon dioxide and so on. So scanning-turning microscopy, let's first of all look at what the main means. Microscopy is quite obvious. We want to modify something, but tunneling might not be able to define a constant everyday life. Tunneling is an effect that we can't explain in classical physics, but it's that we need quantum physics to explain that. So imagine you have a hill and you want to bring an object across that hill. In our classical physics, you will need to put in energy to get it up this hill. And then once it's up there, it has enough energy to roll back down here on the side. Or roll back down, not really, of course. Now, if we think that this object could go through the bottom of this hill to super-tunnel through, right? Like you have a tunnel through your arm to go through. We wouldn't need to put in this energy to go over there. And this is something, of course, that in everyday life doesn't work. Stone doesn't just go through one. But if you scale things down small enough, so say we have now an electron that wants to go from the position of one atom to the position of another atom, then this effect can happen. And that's a quantum effect called electron tunneling. Okay, so we have an electron that goes from one atom to the other, and thereby it can measure a very small current. So how can we use that to do microscopy? We have a sharp tip. So every ball here is one atom, and we have a sun that will also make out of different atoms. We have this tip with one atom at the end, and we bring it close enough to that surface that we can have this tunneling current flow. So this tunneling current I just marked here with this little line. So if it's close enough to that current, and that's what we can measure. But just one measurement of that doesn't deal as a picture. It's just a puncture measurement. And that's where the third term comes in, is scanning. So scanning and tunneling microscopy means we now need to record pixel by pixel, this image by scanning across the surface. So what we need and the requirements for this method is a very sharp tip, because otherwise we don't have a very good resolution. So we need one atom at the end. We need a precise motor, because we need to move across that surface in very small and precise steps. And of course we need to be able to measure these smaller currents. So this is what it looks like if I just demonstrate. So I measure at each pixel the tunneling current, and I record that to assemble my picture of the pixel moving by pixel. This is the method. It might sound like hard with all these requirements, but it was actually developed at the beginning of the 80s by scientists in Switzerland and they received the Nobel Prize just a few years later, because it was really a ground-breaking discovery that by just making this very fine motor we can really monitor things on surfaces very easily. What comes out is an image like this. So in practice we don't do what I showed in this animation. We don't move one pixel per atom. We need to have more pixels per atom. Because otherwise we wouldn't get very nice image. And if we do that here, we have bright blots, but every bright blot is one atom, and we see the arrangement of atoms in the metal surface. But the problem is that, like you've seen in my animation, we need to move, and it's quite slow. It's not as nice as taking a snapshot with a microscope. So to see a time evolving surface we need to make this method faster. So we go faster. The challenge is mainly the steps between the pixels. If we just make it faster, we get into some technical problems because things start to shake. And then if we want to see atoms, we can't really have any vibrations because the vibrations would be bigger than what we're trying to measure. And there are different technical solutions. So my understanding only means unique or the first one or breaking any records. I'm just presenting it because it's one way to do it that I'm using in the lab. In fact, here in Munich at the NNU, at the University here in Munich, there's actually some... there's actually some pioneers that have really made fast, scanning time in the microscopy quite a while ago and are still very active in the scheme. But the solution that I'm presenting today is one that I'm developing together with colleagues here at TOR and also in three years at ELECTRA and it's to use the same instrument but just move the tip a bit differently. So we bring it to the surface and move it in a smooth pendulum motion. So rather than measure pixels, I think so we just record the pixels while we're moving the tip in a smooth way. And this way we don't get this vibration problem we can measure much faster. This tip swings with about 1,000 hertz. So 1,000 times per second. It doesn't need to go very far and first more so it can swim very fast. We then record while it's swinging with about 300,000 times so we record 300,000 pixels per second. The result is that because we're in a sinusoidal motion of our tip and we measure the pixels evenly spaced in time, we need to project the pixels back onto our real space axis and so we have the higher pixel density on the edge of our movie then in the middle and we need to calculate back what pixels were to actually get an image so we don't have nice pixel spacing anymore. But we know the motion so we can calculate and in the end we can receive the movies just going back and forth again over the same spot and surface. We get movies with 20 frames per second. It's very easy. Now this is a rate that's closer to what TV movies are as well about 24 movies. So I'm saying this because now we're getting to the point where our eye time is distinguished between frames anymore. So we really watch things live as they're happening and of course if we then push the frame right in and higher we would have to slow it down and we'll really be able to see what's going on. This is what it looks like in a lab. So this is a really big machine and most of this thing has nothing to do with the microscope. The surroundings are really just to have vacuum, you have controlled environments and so on. So this whole big setup, it always seems to be improvised but it's actually highly sophisticated. Again here, just in this chamber one tiny thing, if you take it out this is my colleague holding it, I'm repairing it at one point. And this is a very fragile tiny thing which is a microscope. And here and here, the most part of what you see is just the motors when these planes are all moves against each other. At the tip you can't even see, it's so small it's one tiny bit of wire with one atom at the end. So it's really a small piece. Okay, so we have this microscope, what can we actually do with it? One thing that we are trying to understand is the raffling and flattening of surfaces. So if you have a surface that's atomically flat, every atom is in the same plane then sometimes you can change your conditions at some gas, molecules to the atmosphere or change the temperature and so on or we can leave the body and we can raffling the surface. So we have lots of steps. And then we might want to flatten it again. Okay, so this is just a bit of a game you can play but also of course it means that you make the surface more or less realistic, so that's a point to do. Here's an example that we have an iron oxide surface. So this is F3 3 or 4. So for F3 3 iron atoms are 4 of such an atom. What we did here is we made some smaller holes into this surface, so the purple is darker and it's a bit deeper sitting. And that's by removing oxygen atoms from the surface because then the iron atoms go down under the surface because they don't have the bonding part anymore in this ratio of 3 to 4. So if you want to flatten it again we need to bring oxygen atoms back so that these iron atoms feel they can come back to the surface and really then make this nice bond again. So that's what we do here. We add oxygen to our atmosphere, we just put some gas around and then we watch what's happening. And here you see lots of stuff moving on this surface. Okay, so this fuzzy thing is stuff that's moving faster and you can see. What we can actually see is that hole is shrinking. So things attach and then grow and then as we watch the hole is getting smaller and smaller and we're really feeling it back up. Now we learn from this that we have a really high mobility of these iron atoms and so we can really try and understand the material properties on an atomic scale. Another example I want to show you today is one that got me very excited for that. So this was really one of the most special days because it showed us that everything works as we want. So, by the way I'm so excited. We have here a little pore. This hexagonal hole maybe make a surface that's called organritoid and we can make it so that we have a little container that's just big enough that you can put a nanoparticle in it. This nanoparticle contains three atoms. It's a palladium 3 nanoparticle, okay? And nanoparticles are everywhere around you. They are not just in the air. It's not on the cruise ship. They're also in the sunscreen. So we really want to understand what they do. They can be useful to use as catalysts and chemical reactions and so we want to understand the properties better. So we have this nanoparticle here and as we watch it, we see that it moves around in this little hole for ever and ever and ever. We've been watching it for hours. Yeah, she's very excited. So this part is moving around but it's not just a nice moving part. I mean we learn a lot from watching this. So we learn, if we look in every frame where this particle is centered, we get then a heat map of all the frames of this moving where each point is where the location was at one point. And we see that there are six locations where this particle is oriented most often. That tells us that the particle feels some forces in that hole even though this little hole looks pretty flat in a microscope, has some structure in there from the atoms underneath and the particle feels these atoms and thereby sits preferentially in some places than others. But in addition to that location information, we also gain a lot from looking at the motion. So if we look at how these dots are connected, then we get more information. We jump from the position 5 to 6 more often than we jump from 5 to 4. And we have three pairs, 5 and 6, 3 and 4 and 1 and 2. These three pairs are easier to jump between where it's between the pairs that's part of the jump and that then tells us again more about this periodicity of the shape and the forces that are acting on this particle in this little hole here. So what we're gaining from this pressure map isn't really accurate information about the forces acting on this particle. So in summary, I've hopefully convinced you that we have a microscope that we can really look at phenomena on the atomic scale, look at molecules, nanoparticles and so on. They're really fascinating phenomena to explore out there. I've just shown you two examples where we're looking at roughening and flattening surfaces and motion of nanoparticles. But of course our aim is to really watch a chemical reaction as it happens live and to understand all this on a very fundamental level. So it's cutting time on a microscope, helping us to understand these fundamental processes and by making it faster we're trying to get the time resolution to understand dynamics as well as structures. Thank you. So, funny video. I have a question here. Like this first slide. This is an experiment. With the war on the particle, the war on other cores and some other particles. So is it this experiment? It's this experiment with the particle we've used it for. Yes, of course. We did lots of experiments for a very long time. This was just the nicest example. But we looked at a different size of particles. You see that large ones, they're just sitting there, these small ones, they're moving well and then atoms, they move much, much faster. So they actually move so fast that when we cool down on a surface, we need to... we still can't have a solace. We need to be even further than we can. So we can find that correlation of the size of the particles. Okay, we have a question here. And then I'll jump back. Thank you very much. How do you manage to get this one to stay here and not move away? Okay. The question was how would we get this one atom at the end of the tip to stay there and not move away? It's a very good question. Actually, it's much easier than you would think. What we need is a very hard material. So we use tungsten or some platinum alloys that are very hard. And then we just need to... The easiest way is you can use some snippets and you pull them and cut them at the same time and if you do it right, you get one atom at the end. And that's actually surprisingly stable. Don't touch it with anything. Don't sneeze on it. But if you don't do that, you're fine. And the more sophisticated way is to edge it down to a more symmetric shape. It's very small, yeah. If you touch the surface once, that's it. Okay, next question at the end. Yeah, I'm looking at this more or less the same question. How do you avoid all the interference from outside and the result of vibration and so on? Okay, yes. Another very good question. How do we avoid vibrations and other influences from the outside? So part of it is when you've seen this big abrasives with this big chamber, it really protects us a lot. So this is mostly the protection from gas molecules from the air because our air is actually so dense that a clean surface will completely oxidize very quickly. We couldn't measure one inch. The other thing is we have this whole machine on soft, damp, neat legs so that the vibrations are isolated. And then inside the chamber, the S10 itself and microscope sets hanging on springs and there are magnets that damp the motion. So if we hit it a little bit, the magnets will compensate and it will stop the shaking very quickly. So yeah, if you have a bad day, you can see every time somebody claps on a normal day as well. I am very sorry that we don't have time for questions, but after the event you can always ask any questions from the partners. You'll be around for a minute, okay? Thank you.