Okay, so let's start.

Okay, welcome back.

So, I'd like to start my lecture with a short presentation of the

lecture.

So, I'd like to start my lecture with a short presentation of the

lecture.

So, I'd like to start my lecture with a short recap of what we did last time.

So, can anybody tell me what a scanning from a microscope is, or what we measure with a scanning from a microscope?

So, the big one is surface topology.

However, and this we will see in today's lecture, we can also measure many other properties of the surface.

For example, with the scanning from a microscope, we do the measuring topology, you measure the distribution of electrons at the surface.

So, we talk mostly about two microscopes, scanning from a microscope and atomic force microscope.

Who can tell me what is the main difference the genes do?

Can a microscope take the mix of the tunneling current between two atoms in the cell?

Whereas the atomic force microscope works on actual contact or tapping or non-contact between the surface.

There is no current between the probe and the surface.

Yes, exactly.

So, the big difference is the exact property that we measure.

So, STM, we measure the tunneling current.

And then in the end we measure the force interaction between the atoms.

That's very easy to remember because it's actually in the name tunneling in the case.

Let's talk a bit more about the tunneling current.

Who can tell me what the tunneling current depends on?

Yes, the voltage.

The voltage, the voltage, the voltage.

Coming up the last one.

So, the distribution of electrons.

If you remember, we had these two potential wells.

The only way to see the shift depth.

Unfortunately, there's only white chalk here.

I like it better, but we have the bias voltage.

We have the distance between the tip and the sample.

We have the work function.

And this is basically the energy you need to remove an electron from an atom.

In German it's called Elektronen aus der Zauber.

And then we have the distribution of electrons.

And then if we go to the atom, the force we measure depends on the distance between the two atoms.

The very famous Lennard-Jones potential.

Attractive and impulsive forces.

What are the names of the two basic force interactions?

We have the Cronowalls, which are attractive and impulsive.

Just as a reminder, I was in the AFM build.

We have surface, we have the Schraubtipp, which is at the end of the bending beam or the center level.

We have some kind of positioning system.

You don't know what it is yet, but we will learn that today.

And then we have laser.

It shines on the back of the bending beam.

It gets collected onto a photoremechanical vector.

All that we measure is this point on our 2D detector.

We go too close to the sample surface.