Dynamical Gap Generation in Topological Insulators

TL;DR

This paper presents a quantum field theory approach to surface states in 3D topological insulators, demonstrating dynamical gap generation under magnetic fields and explaining experimental observations like the zero-Hall plateau.

Contribution

It introduces a relativistic quantum field theoretical model for topological insulator surface states, revealing dynamical gap formation and explaining experimental phenomena.

Findings

Dynamical gap generation due to quantum fluctuations.

Consistent description of Landau level spectrum.

Explanation of zero-Hall plateau via chiral edge states.

Abstract

We developed a quantum field theoretical description for the surface states of three-dimensional topological insulators. Within the relativistic quantum field theory formulation, we investigated the dynamics of low-lying surface states in an applied transverse magnetic field. We argued that, by taking into account quantum fluctuations, in three-dimensional topological insulators there is dynamical generation of a gap by a rearrangement of the Dirac sea. By comparing with available experimental data we found that our theoretical results allowed a consistent and coherent description of the Landau level spectrum of the surface low-lying excitations. Finally, we showed that the recently detected zero-Hall plateau at the charge neutral point could be accounted for by chiral edge states residing at the magnetic domain boundaries between the top and bottom surfaces of the three-dimensional topological insulator.