First-principles study of the structural phase transition and optical properties for MoS2 at high pressure

The structural phase transition, electronic structures, and optical properties of MoS2 are investigated at high pressure via first-principles calculations. Among the 12 structures of MoS2 including stable and metastable structures, the 2R1-MoS2 (described by space group P3m1) and the 3Hb-MoS2 (described by space group P63/mmc) are identified as the stable structures. The results of the electronic structures show that the 2R1-MoS2 transforms from semiconductor to metal and the metallicity of the 3Hb-MoS2 increases under pressure. The optical properties of MoS2 are significantly enhanced and red-shifted in the low-energy region with increasing pressure.