Interacting spin and charge density waves in the kagome metal FeGe

作者：Mason Klemm, Tingjun Zhang, Barry Winn, Fankang Li, Feng Ye, Masaaki Matsuda, Avishek Maity, Sijie Xu, Xiaokun Teng, Y. Umemoto, Bin Gao, Ming Yi, Pengcheng Dai · 发表于：Physical review. B./Physical review. B · 年份：2025 · DOI：10.1103/d88l-4wq8 · 被引用次数：2 · 研究领域：Topological Materials and Phenomena、Organic and Molecular Conductors Research、2D Materials and Applications

Unveiling the interplay between spin density wave (SDW) and charge density wave (CDW) orders in correlated electron materials is important in obtaining a comprehensive understanding of their electronic, structural, and magnetic properties. Kagome lattice materials are interesting because their flat electronic bands, Dirac points, and Van Hove singularities can enable a variety of exotic electronic and magnetic phenomena. The kagome metal FeGe (the B35 phase), which exhibits a CDW order deep within an A-type antiferromagnetic (AFM) phase, was found to respond dramatically to postgrowth annealing---with the ability to tune the CDW repeatedly from long-range order to negligible order. Additionally, neutron scattering studies suggest that incommensurate magnetic peaks that onset at ${T}_{\mathrm{Canting}}={T}_{\mathrm{SDW}}\ensuremath{\approx}60\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ in the system arise from a SDW order instead of the AFM double-cone structure. Here we use inelastic neutron scattering to show that two distinct spin excitations exist below ${T}_{\mathrm{Canting}}$ corresponding to two coexisting magnetic orders in the system in both sets of annealed samples with and without CDW. While CDW order or negligible order can dramatically affect the onset temperature of ${T}_{\mathrm{Canting}}$ and elastic incommensurate magnetic scattering, its impact on low-energy spin fluctuations is more limited. In both samples, a pair of gapless incommensurate spin excitations arisi...