Vacancy-induced suppression of CDW order and its impact on magnetic order in kagome antiferromagnet FeGe

Abstract

Two-dimensional (2D) kagome lattice metals are interesting because they display flat electronic bands, Dirac points, Van Hove singularities, and can have interplay between charge density wave (CDW), magnetic order, and superconductivity. In kagome lattice antiferromagnet FeGe, a short-range CDW order was found deep within an antiferromagnetically ordered state, interacting with the magnetic order. Surprisingly, post-growth annealing of FeGe at 560${}^{\circ }$C can suppress the CDW order while annealing at 320${}^{\circ }$C induces a long-range CDW order, with the ability to cycle between the states repeatedly by annealing. Here we perform transport, neutron scattering, scanning transmission electron microscopy (STEM), and muon spin rotation ($\mu$SR) experiments to unveil the microscopic mechanism of the annealing process and its impact on magneto-transport, CDW, and magnetic properties of FeGe. We find that 560${}^{\circ }$C annealing creates germanium vacancies uniformly distributed throughout the FeGe kagome lattice, which prevent the formation of Ge-Ge dimers necessary for the CDW order. Upon annealing at 320${}^{\circ }$C, the system segregates into stoichiometric FeGe regions with long-range CDW order and regions with stacking faults that act as nucleation sites for the CDW. The presence or absence of CDW order greatly affects the anomalous Hall effect, incommensurate magnetic order, and spin-lattice coupling in FeGe, thus placing FeGe as the only known kagome lattice material with a tunable CDW and magnetic order, potentially useful for sensing and information transmission.

References in corpus (31)

• Theory of Intertwined Orders in High Temperature Superconductors
• Charge density waves and electronic properties of superconducting kagome metals
• Concurrence of anomalous Hall effect and charge density wave in a superconducting topological kagome metal
• Chiral flux phase in the Kagome superconductor AV${}_3$Sb${}_5$
• Discovery of charge density wave in a correlated kagome lattice antiferromagnet
• Novel magnetic states and nematic spin chirality in the kagome lattice metal YMn${}_6$Sn${}_6$
• Intertwined magnetism and charge density wave order in kagome FeGe
• AV${}_3$Sb${}_5$ Kagome Superconductors: Progress and Future Directions
• A hidden constant in the anomalous Hall effect of a high-purity magnet MnSi
• In-plane magnetic field induced double fan spin structure with $\text{c}$-axis component in metallic kagome antiferromagnet YMn${}_6$Sn${}_6$
• Fantastic flat bands and where to find them: The CoSn-type compounds
• Discovery of charge order and corresponding edge state in kagome magnet FeGe
• Microscopic annealing process and its impact on superconductivity in T'-structure electron-doped copper oxides
• Cuprate superconductors as viewed through a striped lens
• Spin-phonon coupling driven Charge density wave in a Kagome Magnet
• Role of oxygen in the electron-doped superconducting cuprates
• Chiral properties of the zero-field spiral state and field-induced magnetic phases of the itinerant kagome metal YMn${}_6$Sn${}_6$
• Magnetic Interactions of the Centrosymmetric Skyrmion Material Gd2PdSi3
• Anisotropic Neutron Spin Resonance in Superconducting BaFe${}_{1.9}$Ni${}_{0.1}$As${}_2$
• Enhanced Spin-polarization via Partial Ge1-dimerization as the Driving Force of the 2$\times$2$\times$2 CDW in FeGe
• Annealing-tunable charge density wave in the kagome antiferromagnet FeGe
• Magnetic interactions and possible structural distortion in kagome FeGe from first-principles study and symmetry analysis
• Competing itinerant and local spin interactions in kagome metal FeGe
• Intriguing Low-Temperature Phase in the Antiferromagnetic Kagome Metal FeGe
• Spin-charge-lattice coupling across the charge density wave transition in a Kagome lattice antiferromagnet
• Reversible Non-Volatile Electronic Switching in a Near Room Temperature van der Waals Ferromagnet
• Annealing-induced long-range charge density wave order in magnetic kagome FeGe: fluctuations and disordered structure
• In-plane uniaxial pressure-induced out-of-plane antiferromagnetic moment and critical fluctuations in BaFe${}_2$As${}_2$
• Complex magnetic and spatial symmetry breaking from correlations in kagome flat bands
• Charge Dynamics of an Unconventional Three-Dimensional Charge Density Wave in Kagome FeGe
• Superconductivity induced by structural reorganization in the electron-doped cuprate Nd${}_{2-x}$Ce${}_x$CuO${}_4$

Cited by in corpus (7)

• Spin Excitations and Flat Electronic Bands in a Cr-based Kagome Superconductor
• Kagome metals
• Tunability of charge density wave in a magnetic kagome metal
• Interacting spin and charge density waves in kagome metal FeGe
• Strain-tunable anomalous Hall effect in hexagonal MnTe
• Beyond kagome: $p$-bands in kagome metals
• Thermoelectric evidence of the electronic structure changes from the charge-density-wave transition in FeGe