Structural phase transition of GeTe under pressure

Structural phase transition of a representative chalcogenide semiconductor, GeTe, is studied with the use of ab initio pseudopotential density functional method. The transition pressure and atomic structures are particularly investigated. By fitting calculated energy-volume data with Birch-Murnaghan equation, we obtained a transition pressure of 3.7 GPa for rhombohedral to NaCl structural transition and 42 GPa for NaCl to CsCl transition, which is in an excellent agreement with experiment [1, 2]. Other structures are also studied for possible transitions at intermediate pressures. The role of Te d orbitals is discussed in regard to the transition pressure and cohesive energy. \newline \newline [1] Onodera A, Sakamoto I, Fujii Y, Mori N and Sugai S, Phys. Rev. B 56 , 7935(1997) \newline [2] N. R. Serebryanaya, V. D. Blank, V. A. Ivdenko, Phys. Lett. A 197, 63 (1995)