Strain-induced Ettingshausen effect in spin-orbit coupled noncentrosymmetric metals

TL;DR

This paper investigates how strain-induced effects in spin-orbit coupled noncentrosymmetric metals lead to novel thermomagnetic transport phenomena, including the Ettingshausen effect, influenced by chiral anomaly, Berry curvature, and external magnetic fields.

Contribution

It demonstrates strain-induced anisotropy and axial electric fields in SOC-NCMs and explores the resulting thermomagnetic effects, including the Berry-curvature-driven anomalous Ettingshausen effect.

Findings

Strain induces anisotropy in spin-orbit coupling.

Strain and magnetic field generate temperature gradients via Nernst-Ettingshausen effect.

Time-reversal symmetry breaking leads to a distinct anomalous Ettingshausen effect.

Abstract

Elastic deformations couple with electronic degrees of freedom in materials to generate gauge fields that lead to interesting transport properties. Recently, it has been well studied that strain-induced chiral magnetic fields in Weyl semimetals lead to interesting magnetotransport induced by the chiral anomaly (CA). Recent studies have revealed that CA is not necessarily only a Weyl-node property, but is rather a Fermi surface property, and is also present in a more general class of materials, for example, in spin orbit-coupled noncentrosymmetric metals (SOC-NCMs). The interplay of strain, CA, and charge and thermomagnetic transport in SOC-NCMs, however, remains unexplored. Here we resolve this gap. Using a tight-binding model for SOC-NCMs, we first demonstrate that strain in SOC-NCMs induces anisotropy in the spin-orbit coupling and generates an axial electric field. Then, using the quasi-classical Boltzmann transport formalism with momentum-dependent intraband and interband scattering processes, we show that strain in the presence of external magnetic field can generate temperature gradients via the Nernst-Ettingshausen effect, whose direction and behavior depends the on interplay of multiple factors: the angle between the applied strain and magnetic field, the presence of the chiral anomaly, the Lorentz force, and the strength of interband scattering. We further reveal that time-reversal symmetry breaking in the presence of an external magnetic field generates the Berry-curvature-driven anomalous Ettingshausen effect, which is qualitatively distinct from the conventional Lorentz-force-driven counterpart. In light of recent and forthcoming theoretical and experimental advances in the field of SOC-NCMs, we find our study to be particularly timely and relevant.