Ab initio calculations of structural and electronic properties of WSe2 compound

The transition-metal dichalcogenides (TMDC) attracted a lot of attention for a variety of applications and more particularly as positive electrodes in lithium batteries. Among these materials the most intensively studied, we find semiconductors such as tungsten diselenide WSe2. In this work, we have perform first-principle calculations to investigate the structural and electronic properties of WSe2 compound, using the density functional theory DFT within the full-potential linearized augmented plane wave method (FP-LAPW) implemented in the code WIEN2k. The Generalized Gradient Approximation (GGA) as proposed by Perdew et al. was used to describe the exchange-correlation potential; and so to obtain the structural properties to assess the equilibrium lattice, the total energy of the system for different values of the primitive mesh and determining the volume at equilibrium, the compressibility modulus and the energy of the ground state, which are close to experimental results reported in the literature. The electronic properties were obtained by calculating the band structure and the density of state "DOS", by using three approaches: Local Density Approximation (LDA), Generalized Gradient Approximation (GGA) and modified Becke-Johnson (mBJ). The calculated energy bands indicate the semiconductor behavior of WSe2 with an indirect band gap of 0.9 eV using LDA, of 1 eV with GGA and 1.18 eV by mBJ. This last band gap value is the closest of the experimental result of 1.2 eV. (C) 2020 The Authors. Published by Elsevier Ltd.