Critical current in semiconductor nanowire Josephson junctions in the presence of magnetic field

Tomohiro Yokoyama,Mikio Eto,Yuli V Nazarov

doi:10.1088/1742-6596/568/5/052035

Abstract

We study theoretically the critical current in semiconductor nanowire Josephson junction with strong spin-orbit interaction. The critical current oscillates with an external magnetic field. We reveal that the oscillation of critical current depends on the orientation of magnetic field in the presence of spin-orbit interaction. We perform a numerical simulation using a tight-binding model. The Andreev levels are calculated as a function of phase difference ψ between two superconductors. The DC Josephson current is evaluated from the Andreev levels in the case of short junctions. The spin-orbit interaction induces the effective magnetic field. When the external field is parallel with the effective one, the critical current oscillates accompanying the 0-π like transition at the cusp of critical current. The distance of cusps increases gradually with increasing of the angle between the external and effective fields. The magnetic anisotropy of critical current is attributed to the spin precession due to the spin-orbit interaction.

Highlights

The spin-orbit (SO) interaction has attracted a lot of interest
When a magnetic field is applied to the junction, the Zeeman effect is taken into account in the nanowire
We introduce a parameter, θB = EZL/(hvF), which means an additional phase due to the Zeeman effect in the propagation of electron and hole

Summary

Introduction

The spin-orbit (SO) interaction has attracted a lot of interest. In narrow-gap semiconductors, such as InAs and InSb, the strong SO interaction has been reported and many phenomena based on the SO interaction are investigated intensively, e.g., spin Hall effect [1]. We investigate theoretically the Josephson junction of semiconductor nanowires with strong SO interaction. A tight-binding model is applied to the normal region with hard-wall potentials forming the nanowire. We focus on the critical current oscillation when an external magnetic field is applied.

Results

Conclusion