  We investigate near-Fermi-energy (EF) element-specific electronic and spin
states of ferromagnetic van der Waals (vdW) metal Fe5GeTe2. The soft x-ray
angle-resolved photoemission spectroscopy (SX-ARPES) measurement provides
spectroscopic evidence of localized Fe 3d band. We also find prominent
hybridization between the localized Fe 3d band and the delocalized Ge/Te p
bands. This picture is strongly supported from direct observation of the
remarkable spin polarization of the ligand p bands near EF, using x-ray
magnetic circular dichroism (XMCD) measurements. The strength of XMCD signal
from ligand element Te shows the highest value, as far as we recognize, among
literature reporting finite XMCD signal for none-magnetic element in any
systems. Combining SX-ARPES and elemental selective XMCD measurements, we
collectively point an important role of giant spin polarization of the
delocalized ligand Te states for realizing itinerant long-range ferromagnetism
in Fe5GeTe2. Our finding provides a fundamental elemental selective view-point
for understanding mechanism of itinerant ferromagnetism in low dimensional
compounds, which also leads insight for designing exotic magnetic states by
interfacial band engineering in heterostructures.
