Edge Channel Transport in InAs/GaSb Topological Insulating Phase

TL;DR

This study investigates edge channel transport in InAs/GaSb heterostructures, demonstrating dominant edge conduction with tunable properties, and provides insights into 2D topological insulators beyond quantized transport regimes.

Contribution

It reveals that InAs/GaSb heterostructures can host edge channels with negligible bulk contribution, and introduces a method to analyze their resistance and scattering characteristics.

Findings

Edge channels dominate transport in certain InAs/GaSb samples.

Resistance fluctuations indicate inelastic scattering in edge channels.

System can be tuned to have conducting edges while maintaining a bulk gap.

Abstract

Transport in InAs/GaSb heterostructures with different InAs layer thicknesses is studied using a six-terminal Hall bar geometry with a 2-$\mu$m edge channel length. For a sample with a 12-nm-thick InAs layer, non-local resistance measurements with various current/voltage contact configurations reveal that the transport is dominated by edge channels with negligible bulk contribution. Systematic non-local measurements allow us to extract the resistance of individual edge channels, revealing sharp resistance uctuations indicative of inelastic scattering. Our results show that the InAs/GaSb system can be tailored to have conducting edge channels while keeping a gap in the bulk region and provide a way of studying 2D topological insulators even when quantized transport is absent.