First-principles study of electronic and sodium-ion transport properties of transition-metal dichalcogenides

Abstract

Two-dimensional (2D) layered materials such as transition-metal dichalcogenides TS[Formula: see text]X[Formula: see text] (T = Mo, W; X = Se, Te) are available in mono and bilayers forms. The Rashba spin splitting is induced by the breaking of inversion symmetry in monolayer. The electronic structure of TS[Formula: see text]X[Formula: see text] is sensitive to an applied electric field. The perpendicular electric field can tune the energy gap. The semiconductor–metal transition appears under the critical electric field in the MoSSe/WSSe heterobilayer, and MoSTe/WSTe heterobilayer exhibits metal character due to spin–orbit coupling. Moreover, the results show that during sodiation/desodiation processes single-phase transition occurs with one one-dimensional (1D) transportation paths of sodium ions in MoS2, suggesting fast diffusion. Our results provide important insights into a wide range of applications of spin-polarized semiconductors and energy storage for transition-metal dichalcogenides TS[Formula: see text]X[Formula: see text].