Supercurrent Reversal in Two-Dimensional Topological Insulators

TL;DR

This paper investigates how an external magnetic field can induce a supercurrent reversal in a two-dimensional topological insulator by closing the hybridization gap and triggering a quantum phase transition, revealing fundamental topological properties.

Contribution

It demonstrates the supercurrent sign reversal associated with a magnetic-field-driven quantum phase transition in 2D topological insulators, linking Josephson effect to topological phase changes.

Findings

Supercurrent reverses sign at the quantum phase transition.

Magnetic field closes the hybridization gap.

Reveals intrinsic topological properties via Josephson effect.

Abstract

We calculate supercurrent across a two-dimensional topological insulator subjected to an external magnetic field. When the edge states of a narrow two-dimensional topological insulator are hybridized, an external magnetic field can close the hybridization gap, thus driving a quantum phase transition from insulator to semimetal states of the topological insulator. We find a sign reversal of the supercurrent at the quantum phase transition revealing intrinsic properties of topological insulators via Josephson effect.