Evaluation performance to assess accurate exchange-correlation functional in van der Waals TMD Materials AB2 (A = Mo, W and B = S, Se and Te)

Two-dimensional (2D) transition metal dichalcogenides (TMDs) show multi-functionality due to their highly adjustable chemical, physical, and electronic properties. Here, structural, electronic, and phonon response are systematically studied for 06 TMDs systems via density functional theory (DFT) simulations. A reversible phase transition is revealed between the semiconducting (2H) phase and the metallic (1T) phase in the stable phases of these TMD systems. Precisely, group-VI TMDs (AB2, A = Mo, W and B = S, Se, Te) are focused in this present calculations. Their electronic behavior is assessed to check the accuracy of few available exchange-correlation (XC) functional, along with van der Waals density functional (vdW-DFs). Here, both spin-orbit coupling (SOC) effects and no SOC (NSOC) cases are considered during the calculations. Changes observed in the electronic band structure and density of states for the 2H and 1T phases are worth noticing, which highlights their potential capabilities for conventional device functionalities. These observations not only enable to find the most accurate XC functional, but also shed light on the potential functionalities of these TMDs materials.