First-principles investigations on electronic, elastic and optical properties of XC (X=Si, Ge, and Sn) under high pressure

An investigation on electronic, elastic, and optical properties of XC (X=Si, Ge, and Sn) under high pressure has been conducted using first-principles calculations based on density functional theory with the plane wave basis set as implemented in the CASTEP code. Our results demonstrate that the sequence of the pressure-induced structure transition of these compounds is from zincblende-type (B3) to NaCl-type (B1) structure. The calculated lattice constants and transition pressures are reported, which are in good agreement with the available experimental results and the previous theoretical data. The elastic constants and anisotropy as a function of pressure are presented. These results suggest technological applications of such materials in extreme environments. Debye temperatures of B3–SnC and B1–SnC are determined for the first time.