# Current Control of Magnetism in Two-Dimensional Fe3GeTe2

## TL;DR

This paper demonstrates how electric current can be used to control the magnetic properties of 2D Fe3GeTe2, enabling tunable magnetic phases and potential studies of phase transitions in two-dimensional systems.

## Contribution

It introduces a simple and powerful current-induced spin torque mechanism in Fe3GeTe2, allowing control over magnetic anisotropy and phase transitions in 2D ferromagnets.

## Key findings

- Current density tunes magnetic anisotropy from easy-axis to easy-plane.
- Spin-orbit torque acts as an effective out-of-equilibrium free energy.
- Potential to study Berezinskii-Kosterlitz-Thouless transition in 2D systems.

## Abstract

The recent discovery of magnetism in two-dimensional van der Waals systems opens the door to discovering exciting physics. We investigate how a current can control the ferromagnetic properties of such materials. Using symmetry arguments, we identify a recently realized system in which the current-induced spin torque is particularly simple and powerful. In Fe3GeTe2, a single parameter determines the strength of the spin-orbit torque for a uniform magnetization. The spin-orbit torque acts as an effective out-of-equilibrium free energy. The contribution of the spin-orbit torque to the effective free energy introduces new in-plane magnetic anisotropies to the system. Therefore, we can tune the system from an easy-axis ferromagnet via an easy-plane ferromagnet to another easy-axis ferromagnet with increasing current density. This finding enables unprecedented control and provides the possibility to study the Berezinskii-Kosterlitz-Thouless phase transition in the 2D XY model and its associated critical exponents.