On the Electronic Structure of 2H-MoS<sub>2</sub>: Correlating DFT Calculations and In-Situ Mechanical Bending on TEM

oleh: Manuel Ramos, Oscar A. López-Galán, Javier Polanco, Miguel José-Yacamán

Format: Article
Diterbitkan: MDPI AG 2022-09-01

Deskripsi

We present a systematic density functional theory study to determine the electronic structure of bending 2H-MoS<sub>2</sub> 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 (<i>E<sub>F</sub></i>) 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 <i>d</i>-character orbitals and the creation of “<i>free electrons</i>”, possibly having an overlap between Mo<sub>-dx</sub><sup>2</sup><sub>-y</sub><sup>2</sup> and Mo<sub>dz</sub><sup>2</sup> orbitals. This research on the metallic transition of 2H-MoS<sub>2</sub> allows us to understand the high catalytic activity for MoS<sub>2</sub> nanostructures as extensively reported in the literature.