Enhanced $d$-$p$ hybridization intertwined with anomalous ground state formation in van der Waals-coupled magnetic metal Fe$_5$GeTe$_2$

TL;DR

This study investigates the temperature-dependent electronic and magnetic structure of Fe$_5$GeTe$_2$, revealing enhanced hybridization and potential exotic ground states in a van der Waals-coupled ferromagnetic metal.

Contribution

It provides a microscopic understanding of the spin-polarized electronic structure and hybridization effects in Fe$_5$GeTe$_2$, highlighting the evolution of electronic states near the Fermi energy.

Findings

Enhanced Fe 3d–Te 5p hybridization at low temperatures

Systematic element-specific XMCD signals observed

Implications for exotic magnetic ground states discussed

Abstract

Fe$_5$GeTe$_2$ is a van der Waals (vdW)-coupled unconventional ferromagnetic metal with a high Curie temperature ($T_C$) exceeding 300 K. The formation of an anomalous ground state significantly below $T_C$ has received considerable attention, resulting in increased interest in understanding the spin-polarized electronic state evolution near the Fermi energy ($E_F$) as a function of temperature. Despite recent extensive studies, a microscopic understanding of the spin-polarized electronic structure around $E_F$ has not yet been established owing to the intrinsic complexity of both the crystal and band structures. In this study, we investigate the temperature dependence of element-specific soft X-ray magnetic circular dichroism (XMCD). A systematic temperature evolution in the XMCD signal from both magnetic Fe and its ligand Te is clearly observed. More importantly, the enhancement in the hybridization between the Fe 3$d$ and Te 5$p$ states in the zero-magnetic field limit is revealed, and we discuss its implications on the possible emergence of an exotic magnetic ground state in Fe$_5$GeTe$_2$.