AB-INITIO CALCULATIONS OF THE PRESSURE-INDUCED STRUCTURAL PHASE-TRANSITIONS FOR 4 II-VI-COMPOUNDS

We report on pseudopotential calculations of the structural properties and pressure-induced solid-solid phase transitions for four II-VI com pounds: ZnSe, ZnTe, CdSe, and CdTe. For each of these compounds, we fi x the zinc-blende structure as the ambient pressure phase and consider the rocksalt, cinnabar, and Cmcm structures as candidates for the hig h-pressure phases. We calculate the transition pressures and the chang es in specific volume for each compound. The pressure dependences of t he structural parameters of the cinnabar and the Cmcm phases are deter mined. The Cmcm structure appears to be a common high-pressure phase f or the II-VI and III-V semiconductors.