Vortex-enabled Andreev processes in quantum Hall-superconductor hybrids

TL;DR

This paper studies how vortices in superconductors affect electron transport in quantum Hall-superconductor hybrids, revealing vortex-mediated Andreev processes and the conditions under which superconducting effects are suppressed.

Contribution

It introduces the role of vortices in mediating Andreev processes in quantum Hall-superconductor systems, a factor often neglected in previous analyses.

Findings

Vortices enable Andreev processes otherwise suppressed.

Finite temperature and many vortices lead to conductance averaging to zero.

Vortices significantly influence transport measurements in these heterostructures.

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 sub-gap 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.