Quantum Oscillations and Magnetoresistance in Type-II Weyl Semimetals - Effect of a Field Induced Charge Density Wave

TL;DR

This paper models the magnetotransport properties of type-II Weyl semimetals, revealing large magnetoresistance and quantum oscillation effects influenced by a field-induced charge density wave transition.

Contribution

It introduces a minimal model incorporating a charge density wave transition in type-II Weyl semimetals, explaining experimental magnetoresistance and quantum oscillation phenomena.

Findings

Large magnetoresistance with B^2 scaling at particle-hole compensation

Transition to B^{0.75} scaling in the quantum limit

Enhanced quantum oscillation amplitude below the CDW transition temperature

Abstract

Recent experiments on type-II Weyl semimetals such as WTe$_2$, MoTe$_2$, Mo$_x$W$_{1-x}$Te$_2$ and WP$_2$ reveal remarkable transport properties in presence of a strong magnetic field, including an extremely large magnetoresistance and an unusual temperature dependence. Here, we investigate magnetotransport via the Kubo formula in a minimal model of a type-II Weyl semimetal taking into account the effect of a charge density wave (CDW) transition, which can arise even at weak coupling in the presence of a strong magnetic field because of the special Landau level dispersion of type-II Weyl systems. Consistent with experimental measurements we find an extremely large magnetoresistance with close to $B^2$ scaling at particle-hole compensation, while in the extreme quantum limit there is a transition to a qualitatively new scaling with approximately $B^{0.75}$. We also investigate the Shubnikov-de Haas effect and find that the amplitude of the resistivity quantum oscillations are greatly enhanced below the CDW transition temperature which is accompanied by an unusual non-monotonous (non-Lifshitz-Kosevich) temperature dependence.