Identifying band structure changes of FePS3 across the antiferromagnetic phase transition

TL;DR

This study uses ARPES to analyze band structure changes in FePS3 across its antiferromagnetic transition, revealing atomic contributions and exchange interactions involved in the phase change.

Contribution

First ARPES investigation of FePS3 below the Neel temperature, linking band structure modifications to magnetic phase transition mechanisms.

Findings

Identified three characteristic band changes across TN involving S 3p, Fe 3d, and P 3p bands.

Demonstrated the involvement of all atoms in the magnetic phase transition.

Provided experimental evidence supporting complex exchange interactions.

Abstract

Magnetic 2D materials enable novel tuning options of magnetism. As an example, the van der Waals material FePS3, a zigzag-type intralayer antiferromagnet, exhibits very strong magnetoelastic coupling due to the different bond lengths along different ferromagnetic and antiferromagnetic coupling directions enabling elastic tuning of magnetic properties. The likely cause of the length change is the intricate competition between direct exchange of the Fe atoms and superexchange via the S and P atoms. To elucidate this interplay, we study the band structure of exfoliated FePS3 by mu m scale ARPES (Angular Resolved Photoelectron Spectroscopy), both, above and, for the first time, below the Neel temperature TN. We find three characteristic changes across TN. They involve S 3p-type bands, Fe 3d-type bands and P 3p-type bands, respectively, as attributed by comparison with density functional theory calculations (DFT+U). This highlights the involvement of all the atoms in the magnetic phase transition providing independent evidence for the intricate exchange paths.