Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe${}_{4.75}$GeTe${}_2$

Abstract

Understanding the ground state of van der Waals (vdW) magnets is crucial for designing devices leveraging these platforms. Here, we investigate the magnetic excitations and charge order in Fe${}_{4.75}$GeTe${}_2$, a vdW ferromagnet with $\approx$ 315 K Curie temperature. Using Fe $L_3-$edge resonant inelastic x-ray scattering, we observe a dual nature of magnetic excitations, comprising a coherent magnon and a broad non-dispersive continuum extending up to 150 meV, 50$\%$ higher than in Fe${}_{2.72}$GeTe${}_2$. The continuum intensity is sinusoidally modulated along the stacking direction $L$, with a period matching the inter-slab distance. Our results indicate that while the dual character of the magnetic excitations is generic to Fe-Ge-Te vdW magnets, Fe${}_{4.75}$GeTe${}_2$ exhibits a longer out-of-plane magnetic correlation length, suggesting enhanced 3D magnetic character. Furthermore, resonant x-ray diffraction reveals that previously reported $\pm$(1/3, 1/3, $L$) peaks originate from crystal structure rather than from charge order.

17 pages, 3 figures, supplementary file

References in corpus (18)

• Magnetic 2D materials and heterostructures
• Orbital-Selective Mott transition out of band degeneracy lifting
• Highly efficient spin-orbit torque and switching of layered ferromagnet Fe3GeTe2
• Detection of a Pair Density Wave State in UTe${}_2$
• Is the Mott transition relevant to f-electron metals ?
• Itinerant ferromagnetism mediated by giant spin polarization of metallic ligand band in van der Waals magnet Fe5GeTe2
• Tuning spin excitations in magnetic films by confinement
• Above-room-temperature ferromagnetism in ultrathin van der Waals magnet
• Reversible Non-Volatile Electronic Switching in a Near Room Temperature van der Waals Ferromagnet
• Self-intercalation as origin of high-temperature ferromagnetism in epitaxially grown Fe5GeTe2 thin films
• Antiferromagnetic fluctuations and orbital-selective Mott transition in the van der Waals ferromagnet Fe3-xGeTe2
• Charge Condensation and Lattice Coupling Drives Stripe Formation in Nickelates
• Enhanced $d$-$p$ hybridization intertwined with anomalous ground state formation in van der Waals-coupled magnetic metal Fe${}_5$GeTe${}_2$
• Novel magnetic excitations beyond the single- and double-magnons
• Quasimolecular electronic structure of the spin-liquid candidate Ba${}_3$InIr${}_2$O${}_9$
• Absence of a Bulk Thermodynamic Phase Transition to a Density Wave Phase in UTe2
• Inelastic neutron scattering determination of the spin Hamiltonian for BaCdVO(PO${}_4$)${}_2$
• Flat bands and magnetism in $\mathbf{F}{\mathbf{e}}_4\mathbf{GeT}{\mathbf{e}}_2$ and $\mathbf{F}{\mathbf{e}}_5\mathbf{GeT}{\mathbf{e}}_2$ due to bipartite crystal lattices