Dielectric and elastic properties of CdP2, ZnP2 and ZnAs2 single crystals

Abstract

The study of dielectric and elastic properties of CdP2, ZnP2, ZnAs2 single crystals was carried out at frequencies 102, 103 , 104, 106 Hz and 107 Hz relatively over the temperature range 78-400 К. Dielectric constant has values (ε = 102–103) over a wide temperature range between 150 K and 400 K. Lower than 150 K the value drops abruptly by almost two orders of magnitude and the dielectric constant is about 9-14 over a temperature range 78-100K. Conductivity σ of materials is composed of two parts: frequency-dependent (hopping) σh part and typical for semiconductors σs part. Hopping conductivity σh ∼ ωα is described by sublinear (α 1) power laws at low and high temperatures respectively. The sound velocities of single crystals were measured over temperature range of 78 - 400 K and elastic constants were calculated. Elastic properties show anomalous softening at small ranges about ΔT = 10-20 K with the following change of curve slope to the temperature axis.