On the Electronic Structure of 2H-MoS₂: Correlating DFT Calculations and In-Situ Mechanical Bending on TEM

We present a systematic density functional theory study to determine the electronic structure of bending 2H-MoS₂ layers up to 75° using information from in-situ nanoindentation TEM observations. The results from HOMO/LUMO and density of states plots indicate a metallic transition from the typical semiconducting phase, near Fermi energy level (E_F) as a function of bending, which can mainly occur due to bending curvatures inducing a stretching and contracting of sulfur-sulfur chemical bonds located mostly over basal (001)-plane; furthermore, molybdenum ions play a major role in such transitions due to reallocation of their metallic d-character orbitals and the creation of "free electrons", possibly having an overlap between Mo_-dx²_-y² and Mo_dz² orbitals. This research on the metallic transition of 2H-MoS₂ allows us to understand the high catalytic activity for MoS₂ nanostructures as extensively reported in the literature.