Transition between ordinary and topological insulator regimes in two-dimensional resonant magnetotransport

TL;DR

This paper theoretically studies the transition between ordinary and topological insulator states in 2D systems, focusing on resonant transport via edge states and how conductance depends on system parameters, with practical implications for measuring edge state properties.

Contribution

It provides a theoretical analysis of resonant transport signatures during the topological phase transition in 2D insulators, including explicit conductance dependence on key parameters.

Findings

Resonant conductance peaks at the transition point due to zero edge modes.

Explicit dependence of conductance on the mass parameter and magnetic field.

Potential method to measure the orbital g-factor of helical edge states.

Abstract

In the two-dimensional case the transition between ordinary and topological insulator states can be described by a massive Dirac model with the mass term changing its sign at the transition point. We theoretically investigate how such a transition manifests itself in resonant transport via localized helical edge states. The resonance occurs in the middle of the band gap due to a zero edge-state mode which is protected by the time-reversal symmetry, also when coupled to the conducting leads. We obtain the explicit dependence of the resonant conductance on the mass parameter and an external magnetic field. The proposal may be of practical use, allowing one to determine the orbital g-factor of helical edge states in two-dimensional topological insulators.