New Routes Towards Disorder Free Topological PbSnTe Nanowire Devices

Hybrid semiconductor-superconductor nanowires are promising building blocks for quantum information processing. However, disorder has been proven to be a limiting factor in conclusively revealing topological phenomena in electronic transport. In addition, scalable and intricate device architectures are required to achieve unambiguous signatures of topology. In this work, we explore the fundamental causes of disorder in devices from an experimental perspective and outline a clear path forward. We present the selective area growth (SAG) platform of large-scale lead tin telluride (PbSnTe) nanowire networks combined with full in-situ device fabrication in ultra high vacuum using molecular beam epitaxy, being a promising path to disorder free topological devices. Our newly developed approaches minimize disorder while allowing for complex and scalable device designs with pristine interfaces and surfaces. We use PbSnTe, a group IV-VI rock-salt semiconductor and predicted topological crystalline insulator, as it is highly suited for quantum applications due to its large dielectric constant, strong spin-orbit coupling, and high carrier mobility. Our new and generalizable methods could contribute to studying the intrinsic transport properties of topological materials.