Breakdown of chiral anomaly and emergent phases in Weyl semimetals under orbital magnetic fields

TL;DR

This paper explores how orbital magnetic fields affect Weyl semimetals, revealing complex phase transitions, emergent layered Chern insulators, and surface state evolutions that differ from continuum models.

Contribution

It uncovers the rich phenomenology of gap opening in lattice Weyl semimetals under orbital magnetic fields, including layered Chern phases and surface state dynamics.

Findings

Orbital magnetic fields induce gap opening and layered Chern insulators.

Anisotropy influences phase transition sequences.

Surface Fermi-arc states evolve distinctly during gap transitions.

Abstract

An external orbital magnetic field applied perpendicular to the separation vector of a pair of Weyl points can couple them and induce a gap in the electronic spectrum. In this work, we investigate the gap-opening behavior in the presence of a lattice, revealing rich phenomenology absent in the continuum picture. Specifically, we address the emergence of layered Chern insulating states, examining how the anisotropy of the Weyl cone dispersion influences the sequence of phase transitions, and establishing connections to the continuum limit. We analyze the evolution of surface Fermi-arc states across these regimes, highlighting their distinct behaviors during the gap-opening transitions.