Ab initio calculations of pressure-induced structural phase transitions of GeTe

Abstract

Structural phase transitions of GeTe are studied with the use of the ab initio pseudopotential density-functional method. Transition pathways and pressures for NaCl-to-CsCl structures are investigated considering three different paths, namely, the Watanabe, Toledano, and modified Buerger pathways. Structural and electronic properties of the phases are also studied near the transition pressures. Our calculations show that GeTe exhibits very complex transition behaviors at intermediate pressures around 20 GPa, implying the existence of mixed phases in this pressure range. It is found that the Te 4d orbitals require careful treatment to properly describe the structural and electronic properties of GeTe.