Longitudinal magnetoconductance and the planar Hall effect in a lattice model of tilted Weyl fermions

TL;DR

This paper investigates how lattice effects and tilt in Weyl fermions influence longitudinal magnetoconductance and the planar Hall effect, revealing mechanisms for negative LMC independent of intervalley scattering.

Contribution

It demonstrates that lattice cutoff nonlinearity can induce negative LMC in tilted Weyl fermions even without intervalley scattering, expanding understanding of chiral anomaly signatures.

Findings

Lattice cutoff causes negative LMC in non-collinear fields.

Tilt parameters significantly affect magnetoconductance behavior.

Phase diagrams map parameter regimes for chiral anomaly detection.

Abstract

The experimental verification of chiral anomaly in Weyl semimetals is an active area of investigation in modern condensed matter physics, which typically relies on the combined signatures of longitudinal magnetoconductance (LMC) along with the planar Hall effect (PHE). It has recently been shown that for weak non-quantizing magnetic fields, a sufficiently strong finite intervalley scattering drives the system to switch the sign of LMC from positive to negative. Here we unravel another independent source that produces the same effect. Specifically, a smooth lattice cutoff to the linear dispersion, which is ubiquitous in real Weyl materials, introduces nonlinearity in the problem and also drives the system to exhibit negative LMC for non-collinear electric and magnetic fields even in the limit of vanishing intervalley scattering. We examine longitudinal magnetoconductivity and the planar Hall effect semi-analytically for a lattice model of tilted Weyl fermions within the Boltzmann approximation. We independently study the effects of a finite lattice cutoff and tilt parameters and construct phase diagrams in relevant parameter spaces that are relevant for diagnosing chiral anomaly in real Weyl materials.