Exchange-Correlation Functional Performance in Transition Metal Dichalcogenides

Two-dimensional (2D) transition metal dichalcogenides (TMDs) exhibit multifunctional properties due to their adaptable chemical, physical, and electronic characteristics. In this study, density functional theory (DFT) simulations systematically assess structural, electronic, and phonon responses of TMD systems. A reversible phase transition between semiconducting (2H) and metallic (1T) phases is identified, focusing on these TMDs. Evaluations of electronic properties involve multiple exchange-correlation (XC) functionals, including van der Waals density functionals (vdW-DFs), with calculations both incorporating and omitting spin-orbit coupling (SOC). Observed changes in band structure and density of states across phases suggest distinct potential for device applications, guiding the selection of optimal XC functionals and revealing the functional versatility of these TMD materials.