Elastic and electronic tuning of magnetoresistance in MoTe$_2$

TL;DR

This study demonstrates that tensile strain can reversibly tune the large magnetoresistance in MoTe₂, a Weyl semimetal, by affecting its electronic structure and phase boundary, with potential implications for device applications.

Contribution

It reveals how uniaxial tensile strain modulates magnetoresistance and phase transitions in MoTe₂, combining experimental and ab initio calculations to understand the underlying mechanisms.

Findings

Magnetoresistance is enhanced by ~30% under tensile strain along the a-axis.

Strain along the b-axis reduces the magnetoresistance by a similar amount.

Tensile strain shifts the phase boundary between monoclinic and orthorhombic phases.

Abstract

Quasi-two dimensional transition metal dichalcogenides (TMD) exhibit dramatic properties that may transform electronic and photonic devices. We report on how the anomalously large magnetoresistance (MR) observed under high magnetic field in MoTe$_2$, a type II Weyl semimetal, can be reversibly controlled under tensile strain. The MR is enhanced by as much as ~ 30 % at low temperatures and high magnetic fields, when uniaxial strain is applied along the $a$-crystallographic direction and reduced by about the same amount when strain is applied along the $b$-direction. We show that the large in-plane electric anisotropy is coupled with the structural transition from the 1T' monoclinic to the Td orthorhombic Weyl phase. A shift of the Td - 1T' phase boundary is achieved by minimal tensile strain. The sensitivity of the MR to tensile strain suggests the possibility of a nontrivial spin-orbital texture of the electron and hole pockets in the vicinity of Weyl points. Our ab initio calculations indeed show a significant orbital mixing on the Fermi surface, which is modified by the tensile strains.