Enhanced d−p hybridization intertwined with anomalous ground state formation in the van der Waals itinerant magnet Fe5GeTe2

Abstract

${\mathrm{Fe}}_{5}{\mathrm{GeTe}}_{2}$ is a van der Waals (vdW)-coupled unconventional ferromagnetic metal with a high Curie temperature (${T}_{\mathrm{C}}$) exceeding 300 K. The formation of an anomalous ground state significantly below ${T}_{\mathrm{C}}$ has received considerable attention, resulting in increased interest in understanding the spin-polarized electronic state evolution near the Fermi energy (${E}_{\mathrm{F}}$) as a function of temperature. Despite recent extensive studies, a microscopic understanding of the spin-polarized electronic structure around ${E}_{\mathrm{F}}$ 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 $3d$ and Te $5p$ states at low temperature in the zero-magnetic field limit is revealed. We discuss the implications of our observation in line with possible emergence of an exotic magnetic ground state in ${\mathrm{Fe}}_{5}{\mathrm{GeTe}}_{2}$.