# Gate Controlled Anomalous Phase Shift in Al/InAs Josephson Junctions

## TL;DR

This paper demonstrates a gate-tunable anomalous Josephson effect in InAs/Al junctions, showing how spin-orbit coupling can be controlled electrically to manipulate supercurrent phase shifts, advancing superconducting spintronics and topological states.

## Contribution

It reports the first tunable anomalous Josephson effect in InAs/Al junctions via gate control of spin-orbit coupling, enabling new spintronics and topological superconductivity applications.

## Key findings

- Gate control of spin-orbit coupling exceeds an order of magnitude.
- Tunable anomalous phase shift $0$ observed in Josephson junctions.
- Potential for new superconducting spintronics and topological devices.

## Abstract

In a standard Josephson junction the current is zero when the phase difference between the superconducting leads is zero. This condition is protected by parity and time-reversal symmetries. However, the combined presence of spin-orbit coupling and magnetic field breaks these symmetries and can lead to a finite supercurrent even when the phase difference is zero. This is the so called anomalous Josephson effect -- the hallmark effect of superconducting spintronics --and can be characterized by the corresponding anomalous phase shift ($\phi_0$). We report the observation of a tunable anomalous Josephson effect in InAs/Al Josephson junctions measured via a superconducting quantum interference device (SQUID). By gate controlling the density of InAs we are able to tune the spin-orbit coupling of the Josephson junction by more than one order of magnitude. This gives us the ability to tune $\phi_0$, and opens several new opportunities for superconducting spintronics, and new possibilities for realizing and characterizing topological superconductivity.