Abstract: Semiconductor nanowires such as InAs and InSb provide a basis for novel low-dimensional quantum devices. Following proposals to engineer Majorana zero modes in these materials, evidence for such modes were reported in highly disordered semiconductor-superconductor devices. However, the level of disorder did not preclude attributing trivial origins to these observations and has motivated significant advances in semiconductor-superconductor devices in order to realize robust Majorana devices.

In this talk, I will discuss how to engineer superconductivity in InSb nanowire devices and realize state-of-the-art quantum transport features in hybrid semiconductor-superconductor devices. In particular, I will explain the development of epitaxial semiconductor-superconductor interfaces, which ensure uniform superconducting coupling to the nanowire and enable ballistic superconducting quantum wires to be realized in InSb. Lastly, I will discuss experiments in progress to study the transition from Andreev to Majorana bound states in ballistic InSb nanowire devices. 

Bio: Stephen Gill is a Ph.D. student at the University of Illinois and a NSF Graduate Research Fellow working in the laboratory of Nadya Mason. He has worked on a range of topics, including strain engineering of graphene, III-V semiconductor nanowires, topological insulators, and superconducting films.