Ab-Initio Investigation of Mechanical Properties of Mx2 Tmdnts

Abstract

This study investigates structural, mechanical, and bonding properties of TMDNTs. In particular, two important quantities, Young’s modulus and Poisson’s ratio, are calculated for 6 zigzag MX2 (M=Zr, Hf; X=S, Se, Te) nanotubes . The computed value of Young’s modulus is greater than that of blue Phosphorus and, in some cases, higher than those of WS2 nanotubes (which are experimentally synthesized). Given the increase in the bond length between M and X atoms, the ratio of Young’s modulus to Poisson’s increases as the atomic number X is reduced. However, there is no significant difference in the aforementioned quantity for ZrX2 and HfX2 nanotubes due to the close bond lengths of Zr-X and Hf-X. The band gap confirms this finding. A Mulliken charge analysis was conducted to investigate the amount of charge transfer between M and X atoms to observe the strength of bond lengths.

Keywords: Transition metal dichalcogenides, Young's modulus, Poison's ratio, Density Functional Theory, mechanical properties