Vortex-enabled Andreev processes in quantum Hall–superconductor hybrids

Abstract

Quantum Hall--superconductor heterostructures provide possible platforms for intrinsically fault-tolerant quantum computing. Motivated by several recent experiments that successfully integrated these phases, we investigate transport through a proximitized integer quantum Hall edge---paying particular attention to the impact of vortices in the superconductor. By examining the downstream conductance, we identify regimes in which subgap vortex levels mediate Andreev processes that would otherwise be frozen out in a vortex-free setup. Moreover, we show that at finite temperature, and in the limit of a large number of vortices, the downstream conductance can average to zero, indicating that the superconductor effectively behaves like a normal contact. Our results highlight the importance of considering vortices when using transport measurements to study superconducting correlations in quantum Hall--superconductor hybrids.