Strain engineering of Janus transition metal dichalcogenide nanotubes: An ab intio study

TL;DR

This study uses first-principles calculations to explore how mechanical strains affect the electronic properties of Janus TMD nanotubes, revealing strain-induced semiconductor-metal transitions and effective mass changes.

Contribution

It provides a detailed ab initio analysis of electromechanical responses in Janus TMD nanotubes, highlighting strain effects on bandgap and charge carrier effective masses.

Findings

Semiconducting nanotubes exhibit bandgap reduction under strain.

Metallic nanotubes remain unaffected by mechanical deformation.

Strain induces semiconductor-metal and n-type to p-type transitions.

Abstract

We study the electromechanical response of Janus transition metal dichalcogenide (TMD) nanotubes from first principles. In particular, considering both armchair and zigzag variants of twenty-seven select Janus TMD nanotubes, we determine the change in bandgap and charge carriers' effective mass upon axial and torsional deformations using density functional theory (DFT). We observe that metallic nanotubes remain unaffected, whereas the bandgap in semiconducting nanotubes decreases linearly and quadratically with axial and shear strains, respectively, leading to semiconductor--metal transitions. In addition, we find that there is a continuous decrease and increase in the effective mass of holes and electrons with strains, respectively, leading to n-type--p-type semiconductor transitions. We show that this behavior is a consequence of the rehybridization of orbitals, rather than charge transfer between the atoms. Overall, mechanical deformations form a powerful tool for tailoring the electronic response of semiconducting Janus TMD nanotubes.