Quantized one-dimensional edge channels with strong spin-orbit coupling in 3D topological insulators

TL;DR

This paper demonstrates millimeter-scale, gate-tunable, quantized edge channels with strong spin-orbit coupling in 3D topological insulators, revealing a new form of one-dimensional quantum transport driven by Rashba effects.

Contribution

It reports the discovery of large-scale, quantized edge channels with strong spin-orbit coupling in 3D topological insulators, distinct from known quantum Hall effects.

Findings

Quantized conductance at 1 e^2/h observed at zero magnetic field

Edge channels can be switched on and off via electrostatic gating

Transport explained by lateral quantum confinement with Rashba spin-orbit coupling

Abstract

A strong coupling between the electron spin and its motion is one of the prerequisites of spin-based data storage and electronics. A major obstacle is to find spin-orbit coupled materials where the electron spin can be probed and manipulated on macroscopic length scales, for instance across the gate channel of a spin-transistor. Here, we report on millimeter-scale edge channels with a conductance quantized at a single quantum 1 $\times$ $e^2/h$ at zero magnetic field. The quantum transport is found at the lateral edges of three-dimensional topological insulators made of bismuth chalcogenides. The data are explained by a lateral, one-dimensional quantum confinement of non-topological surface states with a strong Rashba spin-orbit coupling. This edge transport can be switched on and off by an electrostatic field-effect. Our results are fundamentally different from an edge transport in quantum spin Hall insulators and quantum anomalous Hall insula-tors.