Robust helical edge transport at $\nu=0$ quantum Hall state

TL;DR

This paper reports the observation of robust helical edge states in the $ u=0$ quantum Hall state of HgTe quantum wells, demonstrating nonlocal transport indicative of topologically protected edge conduction in a Dirac material.

Contribution

It provides experimental evidence of helical edge states at $ u=0$ in HgTe quantum wells, advancing understanding of topological quantum Hall effects in Dirac materials.

Findings

Giant nonlocal four-terminal transport observed

Robust helical edge states confirmed in HgTe quantum wells

Topological nature of edge states demonstrated

Abstract

Among the most interesting predictions in two-dimensional materials with a Dirac cone is the existence of the zeroth Landau level (LL), equally filled by electrons and holes with opposite chirality. The gapless edge states with helical spin structure emerge from Zeeman splitting at the LL filling factor $\nu=0$ gapped quantum Hall state. We present observations of a giant nonlocal four-terminal transport in zero-gap HgTe quantum wells at the $\nu=0$ quantum Hall state. Our experiment clearly demonstrates the existence of the robust helical edge state in a system with single valley Dirac cone materials.