2025/10/01 by Mason Klemm, Klemm, Mason L., T. Zhang +16
Physics and Astronomy · #Antiferromagnetism #Charge density wave #FOS: Physical sciences #Inelastic neutron scattering #Magnetic structure #Neutron scattering #Quantum and electron transport phenomena #Quantum, superfluid, helium dynamics #Scattering #Spin (aerodynamics) #Spin density wave #Spin wave #Strongly Correlated Electrons (cond-mat.str-el) #Topological Materials and Phenomena #Wave vector
paper · pdf · doi:10.48550/arxiv.2510.01053
published in arXiv (Cornell University) (Cornell University)
openalex publication_date 2025/10/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Unveiling the interplay between spin density wave (SDW) and charge density wave (CDW) orders in correlated electron materials is important to obtain 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, which exhibits a CDW order deep within an A-type antiferromagnetic (AFM) phase, was found to respond dramatically to post-growth annealing - with the ability to tune the CDW repeatedly from long-range order to no (or extremely weak) order. Additionally, neutron scattering studies suggest that incommensurate magnetic peaks that onsets at TCanting = TSDW ≈ 60 K in the system arise from a SDW order instead of the AFM double cone structure. Here we use inelastic neutron scattering to show two distinct spin excitations exist below TCanting corresponding to two coexisting magnetic orders in the system in both sets of annealed samples with and without CDW. While CDW order or no order can dramatically affect the onset temperature of TCanting 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 arising from the SDW order wavevector coexist with gapped commensurate spin waves from the A-type AFM order across TCanting. Low-energy spin excitations for both samples couple dynamically to the lattice through enhanced magnetic scattering intensity on cooling below TCDW, regardless the status of the static long-range CDW order. The incommensurate SDW order in the long-range CDW ordered sample also induces a tiny in-plane lattice distortion of the kagome lattice that is absent in the no CDW ordered sample.