Masters Defense: Yan Chen

Electronic transport properties in Pb-based hybrid nanowire devices

Abstract
This thesis explores the electronic properties of hybrid semiconductor-superconductor nanowires which hold promise as a material platform to realize topologically protected Majorana quasi-particles. The development of epitaxial materials that exhibits large superconducting hard gap is one of the key directions in this field. Here, we are considering Pb-based materials. The InSb and InAsSb semiconductor nanowires with strong spin-orbit interaction and large Landé-g factor were grown using molecular beam epitaxy. The Pb superconducting film was deposited on the side facets of the nanowires in-situ after the nanowire growth. The devices were fabricated and then characterized electrically at low temperatures. Pb shows normal superconducting transition at critical temperature (7.0K) and critical magnetic field (1.14T) at 1.7 K. When T = 0,the critical field ܪܿ(0) is estimated to be 1.27 T. Then, for InSb/Pb nanowire which is half shell, the pinch off behavior was observed, and for InAsSb/Pb nanowire with shadow junctions, the conductance of quantization behavior at high magnetic fields were realized.

 Zoom link: https://ucph-ku.zoom.us/j/64577932510