Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe4.75GeTe2
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 Fe4.75GeTe2, a vdW ferromagnet with ≈ 315 K Curie temperature. Using Fe L 3-edge resonant inelastic X-...
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Nature Portfolio
2025-07-01
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| Series: | npj Quantum Materials |
| Online Access: | https://doi.org/10.1038/s41535-025-00803-1 |
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| author | V. K. Bhartiya T. Kim J. Li T. P. Darlington D. J. Rizzo Y. Gu S. Fan C. Nelson J. W. Freeland X. Xu D. N. Basov J. Pelliciari A. F. May C. Mazzoli V. Bisogni |
| author_facet | V. K. Bhartiya T. Kim J. Li T. P. Darlington D. J. Rizzo Y. Gu S. Fan C. Nelson J. W. Freeland X. Xu D. N. Basov J. Pelliciari A. F. May C. Mazzoli V. Bisogni |
| author_sort | V. K. Bhartiya |
| collection | DOAJ |
| description | 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 Fe4.75GeTe2, a vdW ferromagnet with ≈ 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 Fe2.72GeTe2. 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, Fe4.75GeTe2exhibits a longer out-of-plane magnetic correlation length, suggesting enhanced 3D magnetic character. Furthermore, resonant X-ray diffraction reveals that previously reported ±(1/3, 1/3, L) peaks originate from crystal structure rather than from charge order. |
| format | Article |
| id | doaj-art-917e09be264149fe949dc6ea7d420766 |
| institution | DOAJ |
| issn | 2397-4648 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | npj Quantum Materials |
| spelling | doaj-art-917e09be264149fe949dc6ea7d4207662025-08-20T03:04:22ZengNature Portfolionpj Quantum Materials2397-46482025-07-011011710.1038/s41535-025-00803-1Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe4.75GeTe2V. K. Bhartiya0T. Kim1J. Li2T. P. Darlington3D. J. Rizzo4Y. Gu5S. Fan6C. Nelson7J. W. Freeland8X. Xu9D. N. Basov10J. Pelliciari11A. F. May12C. Mazzoli13V. Bisogni14National Synchrotron Light Source II, Brookhaven National LaboratoryNational Synchrotron Light Source II, Brookhaven National LaboratoryNational Synchrotron Light Source II, Brookhaven National LaboratoryDepartment of Physics, Columbia University, New YorkDepartment of Physics, Columbia University, New YorkNational Synchrotron Light Source II, Brookhaven National LaboratoryNational Synchrotron Light Source II, Brookhaven National LaboratoryNational Synchrotron Light Source II, Brookhaven National LaboratoryAdvanced Photon Source, Argonne National LaboratoryDepartment of Physics, University of WashingtonDepartment of Physics, Columbia University, New YorkNational Synchrotron Light Source II, Brookhaven National LaboratoryMaterials Science and Technology Division, Oak Ridge National LaboratoryNational Synchrotron Light Source II, Brookhaven National LaboratoryNational Synchrotron Light Source II, Brookhaven National LaboratoryAbstract 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 Fe4.75GeTe2, a vdW ferromagnet with ≈ 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 Fe2.72GeTe2. 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, Fe4.75GeTe2exhibits a longer out-of-plane magnetic correlation length, suggesting enhanced 3D magnetic character. Furthermore, resonant X-ray diffraction reveals that previously reported ±(1/3, 1/3, L) peaks originate from crystal structure rather than from charge order.https://doi.org/10.1038/s41535-025-00803-1 |
| spellingShingle | V. K. Bhartiya T. Kim J. Li T. P. Darlington D. J. Rizzo Y. Gu S. Fan C. Nelson J. W. Freeland X. Xu D. N. Basov J. Pelliciari A. F. May C. Mazzoli V. Bisogni Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe4.75GeTe2 npj Quantum Materials |
| title | Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe4.75GeTe2 |
| title_full | Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe4.75GeTe2 |
| title_fullStr | Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe4.75GeTe2 |
| title_full_unstemmed | Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe4.75GeTe2 |
| title_short | Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe4.75GeTe2 |
| title_sort | magnetic excitations and absence of charge order in the van der waals ferromagnet fe4 75gete2 |
| url | https://doi.org/10.1038/s41535-025-00803-1 |
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