Propriedades físicas das nanoestruturas 2D dos dicalcogenetos do tipo XY2 (X= Mo, W; Y= S,Se) via teoria do funcional da densidade

Abstract

The Transition Metal Dichalcogenide nanomaterials or TMDs are a class of materials with a stoichiometric ratio of the type XY2, where X is a transition metal and Y is a chalcogen, characterized by covalent bonding between X and Y elements exhibiting a polarization caused by the transfer between atoms. These materials exhibit a variety of morphologies, from three-dimensional materials to one-dimensional materials, but in the form of two-dimensional layers, they exhibit a variety of behaviors, making them suitable for various industrial applications. In this study, we model and analyze computationally the structural, electronic, optical and thermodynamic properties through DFT theory (Density Functional Theory) for MoS2, WS2, MoSe2 and WSe2 nanostructures, taking into the approximations: the local density approximation (LDA) and the generalized gradient approximation (GGA) of the optimized structure with energy in the fundamental state. The calculated structural parameters approximate the existing experimental and theoretical data in the literature, and even the energy bandgap characterizes them as semiconductors. The total (DOS) and partial (PDOS) state densities were estimated, indicating the contributions of the atomic orbitals, the light absorptions along polarization planes demonstrate possible applications as sensors in the ultraviolet and visible range. Finally, thermodynamic potentials and specific heat as a function of temperature are analyzed