Suppressing Trivial Edge Conductance in Antimonide-based Quantum Spin Hall Materials*

InAs/GaSb double quantum wells are predicted to possess a quantum spin Hall phase with insulating bulk and conducting helical edge states, which can host Majorana zero-mode particles. The material system is considered a promising and scalable candidate for topological qubits thanks to (1) the absence of an in-plane magnetic field requirement, (2) its ability to electrically tune into and out of the topological regime and (3) the mature growth and fabrication of 2-dimensional III-V heterostructures. However, it suffers from a non-topological parasitic conductance that could hamper the desired topological properties of the helical edge states. In this talk, we will discuss our recent results in solving this technological road block for the material system. By studying different variants of antimonide-based double quantum wells, we are able to reduce the non-topological edge resistance by more than 1 order of magnitude, and significantly improve the bulk resistance in the topological regime.