Magneto-transport in near surface InAs quantum wells in contact with NbTiN

Indium Arsenide (InAs) near surface quantum wells have become the recent focus in topological superconductivity for their use in heterostructures with superconductors. An interface between a superconductor and a quantum Hall edge is predicted to exhibit excitations with non-abelian statistics. A promising candidate for this phenomenon is NbTiN, which can sustain strong magnetic fields in proximity to InAs, which hosts integer quantum Hall states. In this work, we study the proximity effect by monitoring the current flow along the superconductor-semiconductor interface. We find that enhanced conductance could be due to Andreev reflections in the quantum hall regime. In further characterization, we fabricate a hybrid device containing both a superconductor-semiconductor interface and a normal-semiconductor interface, in order to separate the normal and Andreev reflections in presence of strong magnetic fields.
Sandia National Laboratories is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.