Chiral anomaly and longitudinal magnetotransport in type-II Weyl semimetals

TL;DR

This paper investigates the chiral anomaly in type-II Weyl semimetals, demonstrating that positive longitudinal magneto-conductivity occurs in any direction, contrasting previous beliefs about anisotropy.

Contribution

It provides a theoretical analysis of chiral anomaly effects in type-II Weyl semimetals using a quasiclassical Boltzmann approach, showing isotropic magneto-conductivity.

Findings

Chiral anomaly induces positive longitudinal magneto-conductivity in all directions.

Type-II Weyl semimetals exhibit isotropic chiral anomaly effects.

Contrasts with prior assumptions of anisotropy in type-II WSMs.

Abstract

In the presence of parallel electric and magnetic fields, the violation of separate number conservation laws for the three dimensional left and right handed Weyl fermions is known as the chiral anomaly. The recent discovery of Weyl and Dirac semimetals has paved the way for experimentally testing the effects of chiral anomaly via longitudinal magneto-transport measurements. More recently, a type-II Weyl semimetal (WSM) phase has been proposed, where the nodal points possess a finite density of states due to the touching between electron- and hole- pockets. It has been suggested that the main difference between the two types of WSMs (type-I and type-II) is that in the latter, chiral anomaly and the associated longitudinal magneto-resistance are strongly anisotropic, vanishing when the applied magnetic field is perpendicular to the direction of tilt of Weyl fermion cones in a type-II WSM. We analyze chiral anomaly in a type-II WSM in quasiclassical Boltzmann framework, and find that the chiral anomaly induced positive longitudinal magneto-conductivity is present along any arbitrary direction.