Corner Junction as a Probe of Helical Edge States

TL;DR

This paper proposes using inter-edge tunneling in a quantum spin Hall corner junction to detect the helical edge states, highlighting unique conductance signatures caused by electron interactions.

Contribution

It introduces a novel method to probe helical edge states via corner junctions and analyzes the effects of electron interactions on conductance signatures.

Findings

Distinctive four-terminal conductance form identified

Electron-electron interactions lead to intertwined Luttinger parameters

Potential experimental evidence for helical edge states

Abstract

We propose and analyze inter-edge tunneling in a quantum spin Hall corner junction as a means to probe the helical nature of the edge states. We show that electron-electron interactions in the one-dimensional helical edge states result in Luttinger parameters for spin and charge that are intertwined, and thus rather different than those for a quantum wire with spin rotation invariance. Consequently, we find that the four-terminal conductance in a corner junction has a distinctive form that could be used as evidence for the helical nature of the edge states.