Electrified magnetic catalysis in three-dimensional topological insulators

TL;DR

This paper investigates how external electric and magnetic fields induce a novel magnetic catalysis effect in three-dimensional topological insulators, leading to dynamical gap generation and symmetry breaking on the surface.

Contribution

It reveals a new type of magnetic catalysis involving both Haldane and Dirac gaps, emphasizing the electric field's role in symmetry breaking in topological insulators.

Findings

Electric field crucial for dynamical symmetry breaking

Generation of Haldane and Dirac gaps

Large electric field leads to homogeneous surface charge phase

Abstract

The gap equations for the surface quasiparticle propagators in a slab of three-dimensional topological insulator in external electric and magnetic fields perpendicular to the slab surfaces are analyzed and solved. A different type of magnetic catalysis is revealed with the dynamical generation of both Haldane and Dirac gaps. Its characteristic feature manifests itself in the crucial role that the electric field plays in dynamical symmetry breaking and the generation of a Dirac gap in the slab. It is argued that, for a sufficiently large external electric field, the ground state of the system is a phase with a homogeneous surface charge density.