Synthesizing Metastable Rocksalt-Type MgTe Based on High-Pressure Solid-State Phase Transition: A First-Principles Study

The controllability of pressure-induced structural transformation in the hexagonal wurtzite-type MgTe is studied by a first-principles pseudopotential method within the generalized gradient approximation (GGA). Based on the transitional mechanisms of the wurtzite → NiAs and the wurtzite → rocksalt, a special method of loading biaxial pressure on the (010) and (001) planes of an orthorhombic cell is designed. At equal biaxial pressure of 2.75GPa, an abrupt volume collapse is found and the WZ phase transforms into an orthorhombic phase with a tiny distortion. While the pressure decreases to zero, three lattice parameters a, b and c become equal and a metastable rocksalt-type MgTe is obtained.