B013493 - CONDENSED MATTER PHYSICS (INTRODUCTION)

Disordered systems: dynamic response, correlation functions, fluctuation-dissipation. Interaction potentials, static structure of liquids, pair distribution function. Neutron scattering for experimental studies of the static and dynamic structure factor of liquids. Elastic moduli of solids. Phonons. Band structure of solids. Transport properties. Semiconductors. Insulators. Magnetism: phase transitions, elementary excitations in ferromagnetic and anti-ferromagnetic materials. Superconductivity.

N.W. Ashcroft and N.D. Mermin “Solid State Physics”, W. B. Saunders Company (USA, 1976)
P. M. Chaikin and T. C. Lubensky “Principles of Condensed Matter Physics”, Cambridge University Press (Cambridge, 1995).
U. Balucani and M. Zoppi “Dynamics of the Liquid State”
Clarendon Press (Oxford, 1994).

Knowledge of the basic properties of liquids and solids. Collective and self dynamics of disordered systems and their experimental determination by neutron scattering. Band structures. Electron dynamics and transport properties. Screening. Simple theory of electron-phonon interaction. Semiconductors. Statistical mechanics of defects in solids. Elementary excitations in solids.

Advised: Mathematical Methods

Traditional lectures (6 CFU, about 55 hours) with calculations mainly carried out at the blackboard. Limited use of transparencies for the description of experimental data and techniques.

Weekly availability for students: Tuesday 11.00-13.00

Oral exam with a possible short presentation (optional) on one of the subjects of the part regarding liquids and neutron scattering.

Microscopic structure and dynamics of condensed matter: correlation and response functions. Examples of dynamic response: DHO, diffusive models. Density-density autocorrelation function, self and distinct dynamic structure factor. Fluctuation-dissipation theorem and consequences. Fundamentals and experimental aspects of neutron scattering and relation between the neutron double differential cross section and the density-density autocorrelation function. Comparison with other probes of bulk properties. Present applications of inelastic neutron scattering to studies of condensed systems. Models for the dynamic structure factor in the kinetic and diffusive regimes. Viscoelastic model and brief introduction to the memory function formalism. Extraction of collective modes dispersion curves in liquids and relaxation times of the memory function from inelastic neutron scattering data. Static structure of liquids: pair distribution function, static structure factor and their physical meaning. Pair interaction potentials. Recent structural studies of liquids by neutron diffraction. Band structure theory: weak periodic potential; tight-binding method, Wannier functions; APW, KKR, OPW methods; pseudopotentials. Electron-electron interactions, Screening: Thomas-Fermi and Lindhard theories. Semiclassical model of electron dynamics. Semiclassical transport theory. Electron-phonon interaction, Kohn anomalies and Peierls instability. Homogeneous semiconductors: carrier statistics for intrinsic and extrinsic semiconductors. Defects in crystals