Electron heat capacity and moments of the phonon density of states for metals and superconductors

Abstract

A technique for determining the electron heat capacity constant \ensuremath{\gamma} for metals and superconductors is suggested that also allows one to determine the second and the fourth moments of the phonon density of states g(\ensuremath{\omega}) with high accuracy. The method is based on a high-temperature expansion of a lattice heat capacity. All terms of the expansion are taken into account. From experimental heat-capacity results both the lattice and the electron characteristics of ${\mathrm{TmBa}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{7}$ high-temperature superconducting ceramics have been extracted.