Magnetic excitations and absence of charge order in the van der Waals ferromagnet Fe4.75GeTe2

IF 6.2 1区物理与天体物理 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

npj Quantum Materials Pub Date : 2025-07-21 DOI:10.1038/s41535-025-00803-1

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

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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_4.75GeTe₂, a vdW ferromagnet with ≈ 315 K Curie temperature. Using Fe L₃-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_2.72GeTe₂. 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, Fe_4.75GeTe₂exhibits 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.

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范德华铁磁体Fe4.75GeTe2的磁激发与荷序缺失

了解范德华（vdW）磁体的基态对于设计利用这些平台的设备至关重要。本文研究了居里温度为≈315 K的vdW铁磁体Fe4.75GeTe2的磁激发和电荷顺序。利用Fe l3边缘共振非弹性x射线散射，我们观察到磁激发的双重性质，包括相干磁振子和宽的非色散连续体，延伸到150 meV，比Fe2.72GeTe2高50%。连续介质强度沿叠加方向L正弦调制，周期与板间距离相匹配。结果表明，Fe-Ge-Te vdW磁体具有双重磁激励特征，而fe4.75 gete2具有较长的面外磁相关长度，表明其三维磁特性增强。此外，共振x射线衍射表明，先前报道的±（1/3,1/3，L）峰来自晶体结构，而不是电荷顺序。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

npj Quantum Materials Materials Science-Electronic, Optical and Magnetic Materials

CiteScore

10.60

自引率

3.50%

发文量

107

审稿时长

6 weeks

期刊介绍： npj Quantum Materials is an open access journal that publishes works that significantly advance the understanding of quantum materials, including their fundamental properties, fabrication and applications.