# Magnetic anisotropy and phononic properties of two-dimensional ferromagnetic Fe3GeS2 monolayer

## TL;DR

This paper studies the magnetic and phononic properties of a 2D Fe3GeS2 monolayer, revealing its potential for spintronic applications.

## Contribution

The paper reports the first-principles investigation of magnetic anisotropy and phononic properties of Fe3GeS2 monolayer.

## Key findings

- Fe3GeS2 monolayer's ferromagnetic ground state is stable under −1.5%–1.3% biaxial strain.
- Out-of-plane magnetic anisotropy is dominated by dipolar interaction.
- Two single-phonon modes at 9.08 THz and 11.12 THz are identified for quantum resonator design.

## Abstract

In 2023, Fe3GeS2 monolayer with Curie temperature of 630 K is predicted, which is promising to be used in next-generation spintronic devices. However, its magnetic anisotropy and phononic properties are still unclear. In this paper, we implemented the first-principles calculations on Fe3GeS2 monolayer, and found its ferromagnetic ground state with robustness to the −1.5%–1.3% biaxial strain. Meanwhile, the out-of-plane magnetic anisotropy dominated by dipolar interaction is found in Fe3GeS2 monolayer. Finally, we studied the phononic properties to identify the dynamical stability of Fe3GeS2 monolayer and highlight the contribution from the anharmonic interaction of optical phonons to the thermal expansion coefficient. We also find two single-phonon modes can be used to design quantum mechanical resonators with a wide cool-temperature range. These results can provide a comprehensive understanding of the magnetism and phonon properties of two-dimensional (2D) Fe3GeS2, beneficial for the application of 2D Fe3GeS2 in spintronics.

•The ground state of Fe3GeS2 monolayer is robust to the −1.5% to 1.3% biaxial strain•There are two single-phonon modes (9.08 THz and 11.12 THz) in the phonon spectrum•The out-of-plane magnetic anisotropy is dominated by dipolar interaction•The contribution from optical phonons to thermal expansion coefficient is significant

The ground state of Fe3GeS2 monolayer is robust to the −1.5% to 1.3% biaxial strain

There are two single-phonon modes (9.08 THz and 11.12 THz) in the phonon spectrum

The out-of-plane magnetic anisotropy is dominated by dipolar interaction

The contribution from optical phonons to thermal expansion coefficient is significant

Physics; Magnetism