THERMODYNAMICS OF MECHANICAL OSCILLATIONS IN CRYSTALLINE SUPERLATTICES

Abstract

Phonon spectra as well as thermodynamic characteristic of superlattice are analyzed using the method of two-time dependent Green's functions. Free and internal energy of the system as well as specific heat and entropy are found. The temperature behavior of superlattice specific heat is compared with specific heats of bulk structures and thin films. It was shown that at extremely low temperature, superlattice and film specific heats are practically equal and considerably lower than specific heat of bulk sample. The consequences of this fact to the thermal, conducting and superconducting properties of materials was discussed.