84538 - CHARGE TRANSPORT AND OPTICS IN CONDENSED MATTER

Learning outcomes

At the end of the course the students learn the basic aspects of the transport properties of condensed matter, from a classical to a quanto-mechanical approach with non-interacting electrons. The students are able to discuss the main scattering mechanisms controlling charge carrier transport in crystals. The students learn the optical properties of condensed matter and the effect of crystal disorder on the transport properties of condensed matter.

Course contents

1. Electronic Transport in crystals.  Electronic transport in crystals. Definition and modelling of the quantities that describe the electronic transport in crystals (current density, conductivity, mobility) from classical towards semiclassical approximation. Non- interacting electrons in perfect crystals, electron-electron interaction and scattering mechanisms. The models include: Drude model, Sommerfeld model, transport of non interacting Bloch electrons, semiclassical theory of electronic transport, effective mass approach, relaxation time approach, Boltzmann equation. Combined thermal - electrical- magnetic effects (Seebeck, Peltier, magnetoresistance). Electron-electron interaction, Hartree and Hartree-Fock approximations. Scattering mechanisms, Matthiessen rule.
2. Optical Properties of Solids Basic Phenomenological models: description of the optical functions and of their relation with the transport properties, Maxwell Equation in condensed matter, Kramers-Kroning relations. Optical properties of semiconductors: measurement of cyclotronic frequency for the determination of effective mass, absorption spectra of a semiconductor, above and below band gap electronic transitions. Optical properties of insulators, dielectric properties, polarization effects, definition of the optical effective mass, polaron and polaritons, colour centers. Optical properties of metals, plasma frequency, plasmons and surface plasmons. Experimental effects and application of light-matter interaction, Raman and Brillouin spectroscopies.
3. Impurities, Defects and Disorder in solids. Point and extended defects, properties and consequences. Surface effects: surface states, work function definition and measurements, surface -related techniques. Effect of crystal disorder on the transport properties of solids, Mott transition, Urbach tails.

Readings/Bibliography

Neil W. Ashcroft and N. David Mermin, Solid State Physics, Harcourt College Publisher

M Marder, Condensed matter physics, Wiley

M. S. Dresselhaus SOLID STATE PHYSICS PART II, Optical Properties of Solids, on web.mit.edu

Lecture notes available on campus.unibo.it

Teaching methods

Lectures. Group discussion on selected topics.

Assessment methods

Oral exam

Teaching tools

Lecture notes and selected bibliography available on campus.unibo.it

Office hours

See the website of Daniela Cavalcoli