# Electrical control of magnetization in S/F/S junctions on a 3D topological insulator

## TL;DR

This paper explores how the Josephson current in S/F/S junctions on 3D topological insulators can be used to control and stabilize complex magnetization states due to the unique spin-momentum locking of Dirac quasiparticles.

## Contribution

It demonstrates the potential for magnetization control via Josephson effects in topological insulator-based junctions, revealing new ways to manipulate magnetic states.

## Key findings

- Josephson current-phase relation strongly depends on magnetization orientation.
- Voltage-driven regime can split the ferromagnet's easy-axis.
- Unconventional four-fold degenerate ferromagnetic state can be stabilized.

## Abstract

Strong dependence of the Josephson energy on the magnetization orientation in Josephson junctions with ferromagnetic interlayers and spin-orbit coupling opens a way to control magnetization by Josephson current or Josephson phase. Here we investigate the perspectives of magnetization control in superconductor/ferromagnet/superconductor (S/F/S) Josephson junctions on the surface of a 3D topological insulator hosting Dirac quasiparticles. Due to the spin-momentum locking of these Dirac quasiparticles a strong dependence of the Josephson current-phase relation on the magnetization orientation is realized. It is demonstrated that this can lead to splitting of the ferromagnet's easy-axis in the voltage driven regime. We show that such a splitting can lead to stabilization of an unconventional four-fold degenerate ferromagnetic state.