Abstract
Two-dimensional (2D) kagome lattice metals are interesting because their corner sharing triangle structure enables a wide array of electronic and magnetic phenomena. Recently, post-growth annealing is shown to both suppress charge density wave (CDW) order and establish long-range CDW with the ability to cycle between states repeatedly in the kagome antiferromagnet FeGe. Here we perform transport, neutron scattering, scanning transmission electron microscopy (STEM), and muon spin rotation (μSR) experiments to unveil the microscopic mechanism of the annealing process and its impact on magneto-transport, CDW, and magnetism in FeGe. Annealing at 560 °C creates uniformly distributed Ge vacancies, preventing the formation of Ge-Ge dimers and thus CDW, while 320 °C annealing concentrates vacancies into stoichiometric FeGe regions with long-range CDW. The presence of CDW order greatly affects the anomalous Hall effect, incommensurate magnetic order, and spin-lattice coupling in FeGe, placing FeGe as the only kagome lattice material with tunable CDW and magnetic order.
| Original language | English |
|---|---|
| Article number | 3313 |
| Journal | Nature Communications |
| Volume | 16 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2025 |
Funding
C.-L.H. acknowledges Dr. M.K. Lee at the PPMS-16T Lab, Instrumentation Center, National Cheng Kung University (NCKU) for technical support. Y.-C.C. and C.-L.H. are grateful to P.-Z. Hsu and L.-J. Chang at NCKU for the help of Laue diffraction. The neutron scattering and single crystal synthesis work at Rice are supported by US NSF DMR-2401084 and the Robert A. Welch Foundation under Grant No. C-1839, respectively (P.D.). The STEM and 4D STEM characterization at cryogenic temperature performed at Cornell University is supported by US DOE BES DE-SC0023905 (J.J.C). The electron microscopy facilities are supported by the NSF (Platform for the Accelerated Realization, Analysis, and Discovery of Interface Materials) under Cooperative Agreement No. DMR-2039380, and the Cornell Center for Materials Research shared instrument facilities. The Titan Themis 300 was acquired through NSF-MRI-1429155, with additional support from Cornell University, the Weill Institute and the Kavli Institute at Cornell. Z.G. acknowledges support from the Swiss National Science Foundation (SNSF) through SNSF Starting Grant (number TMSGI2_211750). Y.-C.C. and C.-L.H. acknowledge support by the National Science and Technology Council in Taiwan, NSTC 113-2112-M-006-027, and the Higher Education Sprout Project, Ministry of Education to the Headquarters of University Advancement at NCKU. D.N. and T.L.J. are supported by US NSF DMR-2102028. H.C. and Y.Q.H. acknowledge support from the U.S. DOE, BES, Early Career Research Program Award KC0402020, under Contract DE-AC05-00OR22725. M.Y. was supported by the U.S. DOE grant No. DE-SC0021421, the Gordon and Betty Moore Foundation’s EPiQS Initiative through grant No. GBMF9470 and the Robert A. Welch Foundation Grant No. C-2175. This research used resources at the High Flux Isotope Reactor and Spallation Neutron Source, DOE Office of Science User Facilities operated by the Oak Ridge National Laboratory.