Adiabatic elastic moduli in ZnSe : Mn2+ and ZnSe : V2+ crystals

Abstract

The temperature dependences of the elastic moduli C44 (C11 − C12)/2 and Cl = (C11 + C12 + 2C44)/2 of ZnSe : V2+ (impurity concentration, 6 × 1018 cm−3) and ZnSe : Mn2+ (9.4 × 1020 cm−3) are measured in the temperature range 1.4–100.0 K at frequencies of 52 and 156 MHz. The temperature dependences of the adiabatic elastic moduli are derived. It is established that softening of the symmetry modules is observed only in the crystal with an impurity having orbitally degenerate states.