# Signatures of interaction-induced helical gaps in nanowire quantum point contacts

## TL;DR

This paper reports the first direct experimental observation of a helical liquid in InAs nanowires, revealing interaction-induced helical gaps that are prominent even without magnetic fields, with implications for topological quantum computing.

## Contribution

It provides the first direct evidence of interaction-induced helical gaps in nanowire quantum point contacts, highlighting the role of exchange interactions and spin-flipping backscattering.

## Key findings

- Observation of reentrant conductance feature indicating helical liquid
- Helical gaps are prominent without magnetic fields
- Exchange interactions significantly affect transport properties

## Abstract

Spin-momentum locking in a semiconductor device with strong spin-orbit coupling (SOC) is a fundamental goal of nanoscale spintronics and an important prerequisite for the formation of Majorana bound states. Such a helical state is predicted in one-dimensional (1D) nanowires subject to strong Rashba SOC and spin-mixing, its hallmark being a characteristic reentrant behaviour in the conductance. Here, we report the first direct experimental observations of the reentrant conductance feature, which reveals the formation of a helical liquid, in the lowest 1D subband of an InAs nanowire. Surprisingly, the feature is very prominent also in the absence of magnetic fields. This behaviour suggests that exchange interaction exhibits substantial impact on transport in our device. We attribute the opening of the pseudogap to spin-flipping two-particle backscattering. The all-electric origin of the ideal helical transport bears momentous implications for topological quantum computing.