Questions which may guide you to control your understanding

Disclaimer: The following list is a test offer - if you don't need it it will be just skipped.

Elastic properties

• What are stress and strain and how are they linked?
• Which suppositions we usually apply in elasticity theory?
• What is shear stress?
• How many independent component does the elasticity tensor have? Why this number is reduced with respect to "81" and why it depends on the actual system under study?
• How to measure sound velocities? Why there is more than one of them?
• What to learn from the sound velocity experiments on the microscopic properties of a material?

Phonons:

• What is a phonon?
• Why a phonon is considered a quasi-particle?
• How to experimentally determine the phonon dispersion of a material?
• Write energy and momentum conservation laws for an inelastic neutron scattering experiment
• How many phonons can be excited in a material? Is there a way to measure this number?
• What is an acoustic branch?
• Is there always an optical branch? Why?
• Why restricting to the 1st BZ is sufficient?
• Btw, what is the BZ?
• How fast do acoustic wave propagate at q=0, q=pi/a?
• How many branches do you expect for a system with 5 atoms per unit cell?
• Are in general longitudinal or transversal sound waves faster?
• Sketch a typical phonon branch and discuss it
• Can one excite phonons with optical light? Why? Why not?
• Explain Raman scattering
• Explain Brillouin scattering

Thermal Properties

• What is the density of states?
• ... and why is it so important?
• How to calculate the DOS of a given material?
• Does DOS depend on the dimension of a system?
• How to calculate in inner energy U of a lattice?
• What do we learn from measurements of the heat capacity of a material?
• How to measure the heat capacity of a solid?
• Why a material usually expands upon heating?

to be continued... at least if anybody reads it and is interested.