Electron-phonon interactions and instabilities in Weyl semimetals under magnetic fields and torsional strain

TL;DR

This paper investigates how combined magnetic fields and torsional strain influence electron-phonon interactions and potential instabilities in Weyl semimetals, revealing effects of pseudo-magnetic fields and nodal asymmetry.

Contribution

It introduces a continuum model incorporating combined magnetic and strain effects, analyzing electron-phonon interactions and instabilities via renormalization group methods.

Findings

Identification of asymmetric pseudo-magnetic fields at Weyl nodes.

Analysis of fixed points in the coupling parameter flow.

Prediction of lattice instabilities under strong pseudo-magnetic fields.

Abstract

We study the presence of an external magnetic field, in combination with torsional strain, over the electron-phonon interactions in a type I Weyl semimetal. This particular superposition of field and strain, modeled in the continuum approximation by an effective gauge field, leads to an asymmetric pseudo-magnetic field at each Weyl node of opposite chirality. Therefore, we also studied the role of nodal asymmetry in the properties of the system by means of the Kadanoff-Wilson renormalization group and the corresponding flow equations. By solving those, we discuss the evolution of the coupling parameters of the theory, and analyze possible fixed points and lattice (Peierls) instabilities emerging from interactions between phonons with the chiral Landau level in the very strong pseudo-magnetic field regime.