Elastic properties of Janus transition metal dichalcogenide nanotubes from first principles

TL;DR

This study uses first principles calculations to determine the elastic properties of Janus transition metal dichalcogenide nanotubes, revealing trends in their moduli and anisotropy, and developing predictive models.

Contribution

It provides the first comprehensive first-principles analysis of elastic properties of Janus TMD nanotubes, including trends and anisotropy, with a new regression-based predictive model.

Findings

MSSe has the highest moduli, MSTe the lowest.

Anisotropy order: MSTe > MSeTe > MSSe.

Developed a linear regression model for elastic moduli.

Abstract

We calculate the elastic properties of Janus transition metal dichalcogenide (TMD) nanotubes using first principles Kohn-Sham density functional theory (DFT). Specifically, we perform electronic structure simulations that exploit the cyclic and helical symmetry in the system to compute the Young's moduli, Poisson's ratios, and torsional moduli for twenty-seven select armchair and zigzag Janus TMD nanotubes at their equilibrium diameters. We find the following trend in the moduli values: MSSe > MSTe > MSeTe, while their anisotropy with respect to armchair and zigzag configurations has the following ordering: MSTe > MSeTe > MSSe. This anisotropy and its ordering between the different groups is confirmed by computing the shear modulus from the torsional modulus using an isotropic elastic continuum model, and comparing it against the value predicted from the isotropic relation featuring the Young's modulus and Poisson's ratio. We also develop a model for the Young's and torsional moduli of Janus TMD nanotubes based on linear regression.