Ab-initio Study of Polymorphic Phase Transitions of Two Dimensional MoS₂

MoS₂ has been widely studied in recent times because of its intriguing electrical and optical properties and much functionality with other materials. In particular, one of the most interesting properties is that MoS₂ can exist in different structural forms with distinct electronic properties from semiconducting 1H-MoS₂, T’’-MoS₂, to metallic 1T-MoS₂, 1T’-MoS₂ and 1T’’-MoS₂ phases.
Here, using first-principles density functional theory calculations, we systematically investigated the electronic properties and lattice dynamics of five polymorphic phases of MoS2 , and estimated the energy barriers required for phase transition between polymorphic phases depending on the arrangement of S atoms relative to Mo atoms. We expect our studies to provide the fundamental insight into the understanding of the novel polymorphism behavior emerging in other two dimensional materials.