Theory of charge transport in ferromagnetic semiconductor/s-wave superconductor junction

TL;DR

This paper analyzes how Rashba spin-orbit interaction and exchange fields influence tunneling conductance in ferromagnetic semiconductor/superconductor junctions, revealing nonmonotonic and reentrant behaviors of conductance with respect to RSOI.

Contribution

It introduces a theoretical model incorporating RSOI and exchange fields to explain conductance behaviors in ferromagnetic semiconductor/superconductor junctions.

Findings

Normalized conductance peaks at zero voltage depend on RSOI and exchange field.

Andreev reflection probability varies nonmonotonically with RSOI.

Conductance exhibits reentrant behavior at certain interface transparencies.

Abstract

We study tunneling conductance in ferromagnetic semiconductor/insulator/s-wave superconductor junction where Rashba spin-orbit interaction (RSOI) and exchange field are taken into account in the ferromagnetic semiconductor. We show that normalized conductance at zero voltage has a maximum as a function of RSOI for high transparent interface and finite exchange field. This is because Andreev reflection probability shows a nonmonotonic dependence on RSOI in the presence of the exchange field. On the other hand, for intermediate transparent interface, normalized conductance at zero voltage has a reentrant shape at zero or small exchange field with increasing RSOI but is monotonically increasing by RSOI at large exchange field.