Prediction of stable ground-state and pressure-induced phase transition of molybdenum monosulfide.

Several new stable phases of MoS at ambient and high pressures were uncovered by using the global minimization of energy surfaces merging ab initio total energy calculations, and a phase transition order of Imm 2 → Pnma → Pm -3 m was revealed. The transition pressures are 5.5 GPa and 45.3 GPa, respectively, retrieved from the calculated formation enthalpy. The mechanical and dynamical stabilities of these phases were determined by the elastic constants and phonon dispersions. Moreover, the calculated band structures show that the Imm 2 and Pnma phases are indirect band gap semiconductors, whereas the Pm -3 m phase shows metallic character. The electron localization function calculations of these three stable phases were also been analyzed. [ABSTRACT FROM AUTHOR]