Phase Transition in a Wigner Lattice

Abstract

Detailed calculations of the frequency spectrum of lattice vibrations for the body-centered-cubic and face-centered-cubic Wigner lattices in the harmonic approximation show that a phase transition from the body-centered-cubic to either the face-centered-cubic lattice or to some other lattice almost certainly occurs with increasing temperature at sufficiently low densities, but a transition from the body-centered-cubic to the face-centered-cubic lattice does not occur at zero temperature with increasing density in the region where the harmonic approximation is valid. The parameterless frequency spectra for the two lattices, which have been calculated to relatively high accuracy, and their moments are tabulated.