Magnetic anisotropy of critical current in nanowire Josephson junction with spin-orbit interaction

TL;DR

This paper presents a theoretical study of how magnetic field and spin-orbit interaction influence the critical current in nanowire Josephson junctions, revealing anisotropic effects useful for characterizing spin-orbit strength.

Contribution

The work introduces a minimal theoretical model that captures the anisotropic magnetic field dependence of critical current due to spin-orbit interaction in nanowire Josephson junctions.

Findings

Critical current oscillates with magnetic field, showing cusps at 0-$\pi$ transitions.

Spin-orbit interaction causes anisotropic and irregular magnetic field dependence.

The model can help experimentally determine spin-orbit strength and orientation.

Abstract

We develop and study theoretically a minimal model of semiconductor nanowire Josephson junction that incorporates Zeeman and spin-orbit effects. The DC Josephson current is evaluated from the phase-dependent energies of Andreev levels. Upon changing the magnetic field applied, the critical current oscillates manifesting cusps that signal the $0$-$\pi$ transition. Without spin-orbit interaction, the oscillations and positions of cusps are regular and do not depend on the direction of magnetic field. In the presence of spin-orbit interaction, the magnetic field dependence of the current becomes anisotropic and irregular. We investigate this dependence in detail and show that it may be used to characterize the strength and direction of spin-orbit interaction in experiments with nanowires.