Edge channel transport in the InAs/GaSb topological insulating phase

Abstract

Transport in InAs/GaSb heterostructures with different InAs layer thicknesses is studied using a six-terminal Hall bar geometry with a 2-$\ensuremath{\mu}$m edge channel length. For a sample with a 12-nm-thick InAs layer, nonlocal resistance measurements with various current/voltage contact configurations reveal that the transport is dominated by edge channels with a negligible bulk contribution. Systematic nonlocal measurements allow us to extract the resistance of individual edge channels, revealing sharp resistance fluctuations 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 two-dimensional topological insulators even when quantized transport is absent.