 Oh, do you want to use this one? No, this one's okay. There you go. I will tell you my map up here. You can read the chart directly. Perfect. Because now this is lots of results for the host because we've already taken the people. I see. Cross our fingers. Okay, I think it's time to get started. So this final session of the day before we go to the posters and the reception, we've got three talks to one in, sorry, one invited one contributed one invited. The first is a really Pollock from University of Basel. I need the floor is yours. Okay, thank you very much. Thank you all for the introduction. Okay, so let's get started. So the first part will be about this paper we published three years ago in annulators. I have to acknowledge the contribution from Guillame Villena. So Guillame Villena did a lot of molecular dynamics simulation that I will show you today and I am grateful for his calculations. He will have a talk tomorrow. I invite you to go because you will see more of these simulations and you might be interested to discuss with him about this. The second part will be a non published results that will hopefully come soon to publication and it's about this quantum dot super lattices. Okay, so what we do for quite some years now at the University of Basel, we look at friction and mechanics as a single molecule level. So these are two cartoons that basically summarize the kind of experiments we can perform. Here on the right picture on sorry on the left picture we have pulled a few years ago some DNA strands attached on the gold 111 surfaces, and we could probe the force, the mechanical response to pull this object from the surface. On the right parts we can also put on the STM tip or STMI FM tips which is shown by this cluster of let's say copper atoms. We can plug a single molecule and slide it over the surface and we can see really a single point as perity that we can basically model with a typical quantum new some models so this was one of the first experiments. So we work at very low temperature that's really important for this experiment because we want to attach a single molecule to the to the apex of our SPM tip, of course, and I will show you how we do that. So this is the experiments or the machine we use to do this experiment so it's a low temperature STMI FM so I stem for scanning tunneling microscopy FM for atomic force microscopy. It's based on this kind of sensor so the tuning for sensor which is from here. So it's basically STM tip, which is attached to a tuning fork that allow you to measure as well forces so we can do both STM imaging FM imaging, and we can measure forces and local density of states through the STS mode, let's say. So we work in ultra vacuum. We put a sample in this environment which means we have really ultra clean surfaces. We absorb the molecule also in ultra vacuum and we can proceed to some chemical reaction to build up structures that we will then manipulate manipulate manipulation experiments are done at low temperature again at about four to five Kelvin, which allow you to remove any particles. So when you will discuss cooling experiment for example you don't have, I mean, thermal excitation of the of the system. Another aspect which is important we use really really small oscillation amplitude of our FM it's below one answer so it's typically 30 to 50 picometer oscillation and this oscillation scale very well with the size of the molecule we manipulate so you don't detach molecule at every oscillation cycle if you stay in contact and you look at all the molecule actually rearrange under the pulling force for instance. Okay, another aspect which is important for us is that we can proceed to some chemical reaction the idea here is to build up nano structures that we will manipulate afterwards so a good example is this on surface synthesis with woman So basically use usually a precursor that chemist will provide you which is from here, it has bromide atom on the side and you can through annealing of the substrate after after the position of the molecule on the surface you anneal the surface, you split this bromide off the molecule so let's shown here is molecular than in the radical state and they will react together from linear polymeric chains as shown in the middle here. So if you can keep the reaction going on, you will have some processes and you will be able to close some of CC bonds between the structure and form a nice graphene nano ribbons. So years ago my colleague, she actually did an experiment using such a nano ribbons here you see a knife and picture of the structure of the nano ribbons so what you see is actually the hexagonal rings of the graphene. So you can see that as the ribbons length increases, so the force to move this ribbons is not increasing with it so basically it's a, it's a fingerprint of the superlubric behavior of this ribbons on the Gordon and one. And this is something important for us in many different results we have obtained afterwards because we can really pull this ribbons or slide them on the surface, and they have a superlubric behavior. Okay, so today I want to discuss this particular topic is if I compare it to this one what we did we simply in introduce inside the polymer exchange single carbon carbon bonds so they are shown here between this. So, basically you use this precursor you have bromide atoms with the brominates on the surface, the molecule through annealing it polymerize and then you have this pyramid and units which are these things. I'm sorry for that. So these are the pyramid units and they are connected by a single cc bonds between them, which allow you to have more degree of freedom in the system. So, here you see a collection of images so the, this one is actually a nice image of intact. After reaction, you can see clearly that you form the chains as we expect from a chemical point of view. And if you look at the STM image you see that chains are all over the surface, and they are well, I mean, let's say, chemically pure as we expect in terms of chemistry. And there is an important aspect also here, we have quite a substantial in plain bending of the chain and this is due to the single carbon carbon bonds that you have in the structure so we can see really made is good. I mean not twist but some bending of the structure on the surface. And then I will show you now the DFT calculation of the chains in vacuum to show you all the molecule should relax in vacuum. So you should have basically between units, an angle of about 40 degree between units consecutive units. And the reason of that is you have some steric in runs between the auto hydrogen of the perinatal units that force the molecule to twist that way. Now, of course, if you put the molecule on the surface, you start from the from the twisted molecule in vacuum you put it on the surface of pistachios all units are flat line. And you can see through this molecular dynamic simulation, which is basically a relaxation from above room temperature down to low temperature. You see that the molecule wants to create some in plain bending and this is basically because the molecule wants to increase its commensurability with the surface so you want to have a nice absorption of the molecule. And this is also what we see in experiment. So experimentally, we then use one of this molecule so it's a free standing molecule on the gold 111 surface. And this is a molecule here, so by sdn you see that it's about 20 nanometer long that correspond to 35 units. And this is now the trace we obtain experimentally which is a trace showing you the stiffness of the stiffness between your tip and the molecules, which is basically proportional to the force we measure here, which is a frequency and then upon pulling you see a succession of dips all along the curve, which are actually corresponding to the detachment of single units. So you see we pull by about 28 nanometer, which is the length we see by sdn just prior to the manipulation. And this means that we are fully pulling the ribbon from the surface so we simply take it pulling out of the surface and then it's on the tip afterwards after the experiment. Guy was strong enough in terms of simulation to reproduce fully the experiment so here you see that every dips actually correspond to the detachment of single units. You see that the length, the pulling length is also found again in the simulation and we are from this point of view quite happy to have a really good agreement between theory and experiments. But what I want to show you today is that in this course there are much more information that just we pull and we see a number of units. So, as we discuss, let's let's say, as we see now you see the pulling movies from the simulation, and you see that many things are happening so on top you see the top view of the pulling. This is the pulling axis to the left hand side, and this is the side view of the same movies where you see only the detachment of the units. So, first of all, you see that we start from a straight chain and then the chain immediately rotate downwards or upward with respect to the absorption position at the beginning. You also can see on this movie that units are left and right or clockwise and anticlockwise as you are pulling the object. And these are the things we started to look in the experiment. Can we actually see this kind of behavior that you can really well see in the molecular dynamics simulation in our experiments. So the first thing we look, we look more into the detail of the pulling curve. We see that we have always two kinds of detachment lines so that are called that are called here L plus and L minus so you have a short detachment and a long detachment. And they are always alternating because they are colored in gray and white respectively. In the simulation we also found this behavior. Again the movies and you can see at the same time, so you will have too many things, you will have the maximum force to detach the units will change between alternating detachment. So you will have let's say different forces, whether it's detaching clockwise like now or anticlockwise. Okay, we can see from the, from the simulation that stiffness is really well produced. But the additional information is actually the ideal angle so the angle between the two subunits along the system. So you see that you have two kind of rotation. And they are not symmetric. Because the structure is symmetric. In fact, so this is just to summarize the rapid need or let's say you have a force maxima which is changing depending on the detachment if it's clockwise or anticlockwise the work is also different and the dealer angle also different. In fact what you have to look is that upon sliding upon lifting sorry you have the tail of your, of your chain that start to rotate away from its first absorption sites. And this is the two snapshots of the lifting and this are the same for all the units. If you are considering proper attachment, the units will look like this. We will have steric entrance located here on this red area. If you have an anticlockwise rotation with the steric entrance at the opposite side and this are two different configuration and that's is the reason why you see two different lengths help us and then minus in the fourth case. So, besides that, we have also on the surface, the way the molecule slide before its attachment are completely different. So these are the project, the projected trajectories. But we imagine that we select one of these items of units in these items and we compare all the slides on the surface before the attachment. So the length, the attachment length is different, but it does not mean that the unit is jumping away higher than the other ones. Here you can see that the relative height is similar for both units. So the difference is actually all the units travel on the surface, is pulled and then relax after its attachment. And this is what you actually see on these two plots here. We look at all the molecule travel across the surface. So it usually likes to travel along two main direction, which is the one one zero one minus one zero, which are preferential low friction displacement path for the molecule. But you see that the way the path is trajectory is found is completely different between one detachment and the other one. And this is also the reason why we see two different detachment lengths for the clockwise and anti-clockwise units. So just to show you that this is not just an imagination of us in terms of theory and experiment, we actually do see this behavior all along the detachment. In terms of experiment and theory, we are counting the different detachment, you see that for the tendency of having always L plus, then and minus, L plus and minus, which means you have always clockwise, then anti-clockwise, then clockwise, then anti-clockwise, et cetera, et cetera. And this is what you see here. And the reason of that is, is basically when you start detaching from this point here, the molecule will always slide on one direction of the surface, which are always equivalent direction of one minus one zero. So what I show you now on this graph is actually the sliding of the last unit of the chains. And you'll see that it's always the same direction. So because the molecule rotates, the detachment, so the twist cannot be equivalent, because it doesn't follow this direction, but it's put in the equivalent platform, because the tail is actually sliding away. And this is thanks to the in-plane bending you have in these molecules. So this is thanks to the CC bond you introduced in the structure that allows you to have different bending, in-plane bending of the structure upon sliding. So this was just to show you really detailed experiments of what we can do. We have many more different pulling experiment or even sliding experiment. We will talk most probably about some of them. And this is to really remind you that the curve we obtain experimentally are rich. They have a lot of information that are difficult to really interpret without the help of the molecular dynamic simulations. Okay, now I will go to the second part of my talk. How much time I have? Eight minutes. So eight minutes. So now I will talk about completely different system. So we were looking at energy dissipation in actually quantum dots. So this was actually shown in 2010 by the group of Peter Grutter where they use quantum dots. And they could show that when you use an IFM as a gate voltage, so you approach an IFM on top of the quantum dots, you can tune the electron occupancy on the dots. And basically you see the charging of these dots, as well as energy dissipation. So this is what is actually shown here on this piece. So the quantum dot is on top of an insulating substrate. You have a yellow color in yellow to the gas that allows you, which is basically your electron reservoir. And if you apply the right voltage at the tip, you will be able to take an electron from this reservoir and charge the quantum dots. So you can charge with many electrons from zero to six, and each piece will give you dissipation support. So if you now imagine, especially what's going on, here you have four different quantum dots, and they show some different rings. The largest one for a single charging is double charging, and each ring is centered to the dot, because you can charge each of these dots. Now the question we wanted to discuss, I mean what we wanted to look at is what happens when the quantum dots are actually interacting to each other, when they are strongly coupled, because in the previous experiment I showed you, they are actually non-interacting. So here our idea was to actually build a nanoporous network on a metallic surface and confine the electron of the surface, that electron of this metallic surfaces, in this case it's silver 111, and create artificial quantum dots in a way. So each part of this network would actually confine the electron and create a quantum. Then our assumption, and it was discussed this morning by Alexina Olliam, is that force voltage spectroscopy is actually sensitive to quantities that we rarely discuss in IFM, which is the quantum capacitance. The quantum capacitance would scale directly to the local density of states of the quantum dots. So in principle, in the case of a normal metal, whether you have a quadratic dispersion of your surface state, you should have a simple expression of this quantum capacitance. So this could be a quantum capacitance to scale of the effective mass function of your quantum. And this is what we try to basically observe experimentally. So we build two nanoporous networks on the silver 111 surface, we use this molecule, so it's a pure inland unit with oil group at the site. We can by annealing of the substrate promote some tiny reaction. And this will trigger two kinds of sub assembled system on the surface. On the right you see the STM image you will get, and you get another network with different pore size, pore cavities. Let's have a look a bit closer to it. So you have the so called alpha phase, so it's only six membered pores or hexagonal pores. You can see here a better resolution of structure, so it's going to be molecular assemblies for the molecule interacts through hydrogen boundings. And you have the beta phase which contains trigonal, octagonal, hexagonal and nonagonal pores. So this represent different size of the confinement of course. The confinement you can actually interpret is so difficult. The confinement energy from where the quantum dot level will appear depends on E0, so the surface state energy, the position of the surface state, plus the reduced constant, the plant constant, the ternium wave vector and of course m star effective mass of the surface state. So with all these things we can interpret basically where should appears the energy level due to confinement, but we can also probe that using STM. And the idea here is simply to have a clear idea of what's going on in terms of local density of state, what is the band structure of our system. So here you see the calculated structure by GFT and this is the TID spectrum at the middle of the dot, so this is the gray spectrum and on top of the molecule is the dark spectrum. The confinement state is actually located at plus 300 BB, this is this dot. Here you have a second TID that appears below the Fermi level, and this you can consider it as a bonding, bonding anti-bonding basically state. So it would mean already by seeing this that the quantum dots actually strongly interacting to each other. And on the right you have actually cross sections across two of the dots, each of this icon difference after the confinement state and this will be the star which is the bonding states related to the confinement. Just to make a bit more clear, the picture in terms of band structure, you have Fermi level, and you have bonding, anti-bonding states with confinement which are located here when you have the connection band of the silver and below the balance band of the silver. And this is now what you could consider as a local density of state of your system that we want later on to translate to quantum capacitance. We can do the same, but I will go faster on it for the beta assembly, so here we have different force, of course, confinement levels for the confined state are appearing at different energy. If you look at the next element for it again, if you look at the bigger part of the energy flow, then you have also a shift of this bonding energy that is modulated by the variety of four you have in this system. Here again it's what we use for scaling the quantum capacitance in our system. Again the band structure or you can interpret it. Okay, this is now dissipation spectroscopy so what we do we measure the force at the function of the voltage on top of these two assemblies. So these are basically site independent measurements you don't need to be inside the poor on top of the molecule you will have the same response everywhere on top of the molecular. So this is on the alpha superlatives. This is the political parabola of the delta for the force that you have tiny drops in the force, and you have an increase dissipation. Look at the beta that is the same effect of its larger and higher dissipation on the in this system. So I will just show you how we fit these things that I say we use the local entity of state members by sdm to see now from here, it's called it as a quantum capacitance. So this is now the bonding and I'm taking states as determined by sds. We put it in the force formula, which is shown on top, where sqe is a quantum capacitor. So we just to make it simple. So as soon as you are before this value in terms of energy, you will be accessing this kind of quantum capacity. And this is now force waves. And you can then vary the force and get the data and you see in yellow, the spectra as measured and in dark, this is a fit. So you see that it's quite coincide. I mean, there is a good agreement, let's say. So you can keep repeating this measurement at different heights. So the only thing we change is the tip sample separation. And you see that this is a clear phenomenon that you see even at large distance between the tip and the sample. So there is an interesting things here, you have different quantities we have the threshold voltage where you start to access. You can see that this is a shadowing of states, you have star which is a threshold force and star which will be the dissipation. And all these quantities are shown here, they are almost always constant everywhere. So basically, even if you increase the tip sample separation, you still see the same dissipation magnitude. And this actually is not really intuitive at first sight. It means that you are created fluctuating current in your sample, but there is no transfer between your tip and your sample. So basically your potential is creating current between the dots, but you have no transfer from the tip and the sample. And this is because if it would be the case, you should have a decrease of the dissipation as you increase the distance. We can also scale because it's a really packed quantum dot superlatives of strongly interacting quantum dot we can from the IFM measurement we can try to get access to tuning range between these dots. So this is something that was introduced in IFM many years ago. So basically you have to look at the width of the peak and do the force of the drop of the force. We could relate this to some frequencies so you see that for the alpha phase would be in the order of 69 kilowatts, I mean 69, 79 kilowatts for the beta phases would be higher. This would, let's say, this would show you how easy it is to transfer electron between the dots in your delocalized states. And with that, I just want the last slide, I promise. I just want to show you that we can also image the things, I mean the dissipation. We will go ahead and talk about that. You can have access to the force. You will see different contrasts when you add the voltage threshold. And you will see the dissipation more over the assembly. The force will change and the voltage will be greater than 0. And you see the dissipation coming from the voltage. And we are really inducing current in the molecular asymptotes with an effect from this. I want to acknowledge that most of these components are measurements. Yeah, maybe not all the insulation on the lifting belt, there's many more. And my office and our kids that provide us really nice money. Right, we have time for a couple of questions. Very nice and clear talk. In the first part of your lecture, you measured the modulus when you put these things is K effective or what that is. That was on your slide number 15. And at the same time at all the same slide you showed the force as a function of distance. The force linear, right but the modulus is defined as force derivative of force with respect to distance. So I just wonder why the modulus is not constant. Slide number 15. This one, you show us a force as a function of distance which is just linear. And the derivative of the force with respect to distance should be a constant right, but that is a definition of the modulus. And I wonder why you get the spike like structure out of these data. This is the one the one on the top. Yeah, this is one in the middle. Okay, I know I understand so. So, okay, I understand so. Okay, the experiment. A bit more information. Just here. I see we are also. I understand why you get that. I just don't understand how you can get these data out of a linear force for the system. I don't understand how it holds me. Well, the one that was just defined as the next. Yes. Contact. So it's essentially constant and then it drops. The top part is not very fast. Okay. So the problem is the stiffness is measured through an oscillation. Right. And this oscillation has given characteristic time. So you're not able to actually see with this oscillation. So this, when the unit snaps off, it looks much longer gross. And it really is. And this is a set of solutions that you can see. And the duration of this oscillation is larger than the process itself. So it looks like this shoulder on the tip. And the other part you can see also in the simulation, there are some, some, some, if you look at the road, yes, you see also some modulation that this is related with the sticks. So we need to move on to the next talk, but we'll encourage more discussion posters. So let's thank from you again.