Charge transport in two dimensional electron gas/superconductor junctions with Rashba spin-orbit coupling

TL;DR

This paper investigates how Rashba spin-orbit coupling affects tunneling conductance in 2D electron gas/superconductor junctions, revealing barrier-dependent suppression and reentrant behavior, differing from ferromagnet/superconductor systems.

Contribution

It provides a theoretical analysis of tunneling conductance considering Rashba spin-orbit coupling, including effects of barrier strength and conductance reentrance, applicable to arbitrary velocity operators.

Findings

Conductance suppressed by RSOC at low barriers

Conductance nearly independent of RSOC at high barriers

Reentrant conductance behavior at intermediate barriers

Abstract

We have studied the tunneling conductance in two dimensional electron gas / insulator / superconductor junctions in the presence of Rashba spin-orbit coupling (RSOC). It is found that for low insulating barrier the tunneling conductance is suppressed by the RSOC while for high insulating barrier it is almost independent of the RSOC. We also find the reentrant behavior of the conductance at zero voltage as a function of RSOC for intermediate insulating barrier strength. The results are essentially different from those predicted in ferromagnet / superconductor junctions. The present derivation of the conductance is applicable to arbitrary velocity operator with off-diagonal components.