Physics of solids 1

A.Y. 2020/2021
Overall hours
Learning objectives
This course targets a general understanding of a broad range of fundamental phenomena and properties of solid-state matter. The course covers electronic,
vibrational, and spectroscopic properties of crystals, plus heat and electricity transport
Expected learning outcomes
The student is expected to learn in detail:

1. Periodic crystals and crystal lattice. Direct and reciprocal lattice.
X-ray diffraction. Miller indices. Form factor and structure factor.
Packing fraction. Quasicrystals (brief).

2. Total cohesive energy of the crystals. Simple examples of crystals of
noble gases and ionic solids. The density functional theory (DFT) for
calculating total adiabatic energy of a solid. Similarities and differences
with Hartree-Fock. Approximate density functionals: the Thomas-Fermi and
Kohn-Sham methods; the local density approximation (LDA).

3. Linear elastic response and the elastic constants of a solid.

4. Atomic motions in a crystalline solid: the harmonic approximation,
lattice vibrations and phonons. Phonon dispersions in special directions
of cubic crystals: longitudinal modes and transverse modes. Phonons in
3-dimensional solids in arbitrary crystal directions. The LO-TO splitting
in cubic crystals.

5. Methods for measuring the dispersion curves of phononic frequencies.
Brief review of the thermal properties of phonons, the Debye model.

6. Anharmonic effects in crystals: the Gruneisen theory of the thermal
expansion of solids, collisions between phonons, thermal conductivity.

7. A simplified model for the motion of electrons in metallic solids: the
jellium model, and its DFT solutions. Charge and heat conduction in the
relaxation-time approximation. Hall coefficient.

8. Band theory of solids: electrons in a periodic potential, models and
methods for the calculation of the electronic bands (brief). General
features of the structural and electronic band calculations of crystals
within the DFT approach. Semiclassical motion of the electrons in
crystals, effective mass. Holes and their motion.

9. Semiconductors: the valence and conduction bands, intrinsic and doped
semiconductors, carriers, mobility, conductivity, Hall effect, cyclotron
resonance. A few transport and out-of-equilibrium effects. The p-n
junction. A panorama of inhomogeneous semiconductor applications.

10. Metals: AC response and conductivity. The Boltzmann equation. Optical
response of the electrons and spectroscopies. Out-of-equilibrium and
thermoelectric effects.

11. Elements of electron-electron correlation effects and screening effects. Excitonic
effects: optical gap and quasiparticle gap. Optical excitations: plasmons,
Course syllabus and organization

Unique edition

Lesson period
Second semester
FIS/03 - PHYSICS OF MATTER - University credits: 6
Lessons: 42 hours
Professor: Manini Nicola
Tuesdays 2pm - 5pm
office, via Celoria 16, room A/T/C11