DFT+DMFT investigation of the magnetic phase transition in the itinerant ferromagnet Fe$_{3}$GaTe$_{2}$

TL;DR

This study uses advanced electronic structure calculations to explore the magnetic phase transition in Fe$_{3}$GaTe$_{2}$, revealing the role of flat bands and many-body interactions in enhancing its Curie temperature for spintronic applications.

Contribution

It provides the first detailed analysis of the electronic and magnetic properties of Fe$_{3}$GaTe$_{2}$ using DFT+DMFT, highlighting the impact of flat bands and strong correlations on its high Curie temperature.

Findings

Emergence of quasi-particle flat bands driven by many-body interactions.

Hybridization of flat bands at low temperatures suggests heavy fermion behavior.

Tunable flat bands near the Fermi level may enable high-temperature ferromagnetism.

Abstract

Finding and designing ferromagnets that operate above room temperature is crucial in advancing high-performance spintronic devices. The pioneering van der Waals (vdW) ferromagnet Fe$_{3}$GaTe$_{2}$ has extended the way for spintronic applications by achieving a record-high Curie temperature among its analogues. However, the physical mechanism of increasing Curie temperature in this material still needs to be explored. Here, we systematically investigate the electronic structures and magnetic properties of Fe$_{3}$GaTe$_{2}$ as a function of temperature using strongly correlated calculations, reconciling the dual nature of $d$-electrons with both localization and itinerant characters. Significantly, our study reveals the emergence of quasi-particle flat bands driven by many-body interactions, which enhance magnetic stability through a positive feedback mechanism. Furthermore, our results demonstrate the hybridization of these flat bands at low temperatures, indicating the possible presence of heavy fermion behavior in this system. Our findings suggest that tunable flat bands near the Fermi level may serve as a key factor in realizing materials with high magnetic transition temperatures and strong magnetic anisotropy. This research provides a promising pathway for exploring next-generation spintronic devices utilizing vdW flat band systems.