Seeing the unseen

The way atoms and molecules organize in space impacts the properties of the materials they form. Nowadays, we count with very specialized microscopes to try to look at that organization, not only by taking pictures of the atoms but by recording in real-time how they behave while doing their job. Secretly recording them in their native environment gives us crucial information to improve all devices that surround us and brings understanding to very complex questions about the formation and degradation processes of materials in the world.

In the universe of atoms, the laws of classical physics are violated. For example, an electron of an atom in a conductive solid is everywhere in the solid. How to see it? We can't. Except when one approaches very closely to the surface of an object and that with a probe, one begins to interact with electrons. As they are trapped inside the material, it is difficult to extract them, except by a mechanism called "tunneling effect". We will see during the presentation how to "see" these electrons and especially how to measure their energy thanks to what we call tunneling spectroscopy.