Quantum Oscillations of The Positive Longitudinal Magnetoconductivity: a Fingerprint for Identifying Weyl Semimetals

TL;DR

This paper presents a unified theory explaining positive longitudinal magnetoconductance in Weyl semimetals, revealing quantum oscillations as a key signature for identifying these materials, supported by experimental observations.

Contribution

It introduces a comprehensive analytical framework connecting classical and quantum regimes, highlighting quantum oscillations as a fingerprint for Weyl semimetals with chiral anomaly.

Findings

Quantum oscillations originate from oscillations of the nonequilibrium chiral chemical potential.

Positive LMC exhibits periodic-in-1/B quantum oscillations.

Quantum oscillations serve as a fingerprint for Weyl semimetals with chiral anomaly.

Abstract

Weyl semimetals (WSMs) host charged Weyl fermions as emergent quasiparticles. We develop a unified analytical theory for the anomalous positive longitudinal magnetoconductance (LMC) in a WSM, which bridges the gap between the classical and ultra-quantum approaches. More interestingly, the LMC is found to exhibit periodic-in-$1/B$ quantum oscillations, originating from the oscillations of the nonequilibrium chiral chemical potential. The quantum oscillations, superposed on the positive LMC, are a remarkable fingerprint of a WSM phase with chiral anomaly, whose observation is a valid criteria for identifying a WSM material. In fact, such quantum oscillations were already observed by several experiments.