Theory of the Temperature Dependence of the Electric Field Gradient in Noncubic Metals

Abstract

The temperature dependence of the electric field gradient $\mathrm{eq}(T)$ in noncubic metals is calculated within a pseudopotential approach including the influence of lattice vibrations. The resulting $\mathrm{eq}(T)$ factorizes into a Debye-Waller factor and a lattice sum over screened ions. The accurately measured $\frac{\mathrm{eq}(T)}{\mathrm{eq}(0)}$ values for In, Cd, Zn, Sb, and Sn are quantitatively reproduced using known data for the lattice constants and for the mean-square atomic displacements.