AB INITIO STUDY OF STRUCTURAL PROPERTIES OF INTERMETALLIC COMPOUNDS PtX (X = Si, Ge, Sn AND Pb) UNDER HIGH PRESSURE

Abstract

High pressure effect on the structural evolution properties of intermetallic compounds PtX (X = Si, Ge, Sn AND Pb ) was studied based on the first principle density functional theory. The compressibility of PtSi and PtGe under high pressure presents anisotropic behavior. The crystal stacking characteristic of the PtX (X = Si and Ge ) along the three axes may be responsible for their anisotropic axial compressibility under high pressure. The sequence of axial compressibility for PtSi is c < a < b, whereas PtGe exhibits the sequence of a < c < b. The pressure derivative of c/a was qualified to be 8.92×10-4 GPa -1 and 1.38×10-3 GPa -1 for PtSn and PtPb , respectively. The applied pressure stabilized the crystal structures of PtSn and PtPb .