The development of nanotechnology has unambiguously shown that, at the nanoscale, the customary laws of macroscopic Physics (such as Ohm's law) break down and electrons can behave in a fully quantum mechanical way. Indeed, under appropriate conditions, their wavelike nature makes electronic transport coherent and characterized by peculiar laws, different from both the Statistical Mechanics of macroscopic systems and from the Physics of microscopic molecules. These discoveries have paved the way to a research field called Mesoscopic Quantum Physics. The purpose of this course is to provide an introduction to Mesoscopic Systems, pointing out their main physical features, the theoretical modeling, and the experimental realizations. After a short primer on Quantum Mechanics and on the electronic properties in solids, we shall describe various quantum mesoscopic effects such the Aharonov-Bohm effect, Weak localization, Fabry-Pérot quantum interferometry. Then, the course will present the Scattering-Matrix formalism introduced by Landauer and Buettiker to account for the quantum coherence effects in an arbitrary mesoscopic system. If time allows that, we shall also analyze mesoscopic effects in the transport properties of carbon-based materials (particularly nanotubes and graphene), and/or in superconductors.

Some knowledge of Condensed Matter Theory and Quantum Mechanics is preferable, although it is not mandatory (in the Introductory part of the course the main ingredients needed for Mesoscopic Physics will be reviewed)

1. Short survey about Quantum Mechanics 2. Electronic band structures in materials, nanostructures, experimental realizations. 3. Introduction to Mesoscopic Physics, characteristic length-scales and purely mesoscopic effects 4. Modeling mesoscopic systems: the Landauer-Buettiker formula and its applications to quantum wires and Carbon Nanotubes. 5. Generalization to the multi-channel case: conductance quantization and applications to Quantum Point Contacts 6. (Carbon-based materials: Introduction, mesoscopic effects and applications. AND/OR Superconductivity: Introduction and mesocopic effects in superconductors)

In presenza

Presentazione orale

P.D.1-1 - Febbraio