# Chiral anomaly as origin of planar Hall effect in Weyl semimetals

## TL;DR

This paper demonstrates that the chiral anomaly in Weyl semimetals leads to a planar Hall effect, which occurs when electric and magnetic fields are in the same plane, providing a new experimental signature of topological properties.

## Contribution

It introduces the concept that chiral anomaly and Berry curvature effects cause a measurable planar Hall effect in Weyl semimetals, with specific predictions for experimental verification.

## Key findings

- Planar Hall effect arises in Weyl semimetals due to chiral anomaly.
- PHE occurs when current, magnetic field, and voltage are coplanar.
- Distinct signatures predicted for type-I and type-II Weyl semimetals.

## Abstract

In condensed matter physics, the term "chiral anomaly" implies the violation of the separate number conservation laws of Weyl fermions of different chiralities in the presence of parallel electric and magnetic fields. One effect of chiral anomaly in the recently discovered Dirac and Weyl semimetals is a positive longitudinal magnetoconductance (LMC). Here we show that chiral anomaly and non-trivial Berry curvature effects engender another striking effect in WSMs, the planar Hall effect (PHE). Remarkably, PHE manifests itself when the applied current, magnetic field, and the induced transverse "Hall" voltage all lie in the same plane, precisely in a configuration in which the conventional Hall effect vanishes. In this work we treat PHE quasi-classically, and predict specific experimental signatures for type-I and type-II Weyl semimetals that can be directly checked in experiments.