Fermion-boson many-body interplay in a frustrated kagome paramagnet

Abstract

Kagome-net, appearing in areas of fundamental physics, materials, photonic and cold-atom systems, hosts frustrated fermionic and bosonic excitations. However, it is extremely rare to find a system to study both fermionic and bosonic modes to gain insights into their many-body interplay. Here we use state-of-the-art scanning tunneling microscopy and spectroscopy to discover unusual electronic coupling to flat-band phonons in a layered kagome paramagnet. Our results reveal the kagome structure with unprecedented atomic resolution and observe the striking bosonic mode interacting with dispersive kagome electrons near the Fermi surface. At this mode energy, the fermionic quasi-particle dispersion exhibits a pronounced renormalization, signaling a giant coupling to bosons. Through a combination of self-energy analysis, first-principles calculation, and a lattice vibration model, we present evidence that this mode arises from the geometrically frustrated phonon flat-band, which is the lattice analog of kagome electron flat-band. Our findings provide the first example of kagome bosonic mode (flat-band phonon) in electronic excitations and its strong interaction with fermionic degrees of freedom in kagome-net materials.

arXiv commentTo appear in Nature Communications (2020)

References in corpus (25)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Weyl and Dirac Semimetals in Three Dimensional Solids
• Topological Photonics
• Moire bands in twisted double-layer graphene
• Evidence for ubiquitous strong electron-phonon coupling in high-temperature superconductors
• Analogs of quantum Hall effect edge states in photonic crystals
• Quantum Spin Liquids
• Massive Dirac fermions in a ferromagnetic kagome metal
• Dirac fermions and flat bands in the ideal kagome metal FeSn
• Large intrinsic anomalous Hall effect in half-metallic ferromagnet Co3Sn2S2 with magnetic Weyl fermions
• Evidence for Magnetic Weyl Fermions in a Correlated Metal
• Heavy Fermions and Quantum Phase Transitions
• Negative flat band magnetism in a spin-orbit coupled correlated kagome magnet
• Giant and anisotropic many-body spin-orbit tunability in a strongly correlated kagome magnet
• Interplay of electron-lattice interactions and superconductivity in Bi2Sr2CaCu2O8+d
• Intrinsic Quantum Anomalous Hall Effect in the Kagome Lattice Cs2LiMn3F12
• Orbital-selective Dirac fermions and extremely flat bands in frustrated kagome-lattice metal CoSn
• Multiple Bosonic Mode Coupling in Electron Self-Energy of (La_2-xSr_x)CuO_4
• Direct extraction of the Eliashberg function for electron-phonon coupling: A case study of Be(1010)
• Anomalous dressing of Dirac fermions in the topological surface state of Bi2Se3, Bi2Te3, and CuxBi2Se3
• Evidence of a spin resonance mode in the iron-based superconductor Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ from scanning tunneling spectroscopy
• Many-body Resonance in a Correlated Topological Kagome Antiferromagnet
• Quasiparticle Interference and Strong Electron-Mode Coupling in the Quasi-One-Dimensional Bands of Sr${}_2$RuO${}_4$
• Quantifying many-body effects by high-resolution Fourier transform scanning tunneling spectroscopy
• Tracing the electronic pairing glue in unconventional superconductors via inelastic Scanning Tunneling Spectroscopy

Cited by in corpus (32)

• Discovery of unconventional chiral charge order in kagome superconductor KV3Sb5
• Topological kagome magnets and superconductors
• Kagome superconductors AV${}_3$Sb${}_5$ (A=K, Rb, Cs)
• Weyl, Dirac and high-fold chiral fermions in topological quantum materials
• Electronic nature of chiral charge order in the kagome superconductor CsV3Sb5
• Intrinsic nature of chiral charge order in the kagome superconductor RbV3Sb5
• Probing topological quantum matter with scanning tunnelling microscopy
• Realizing Kagome Band Structure in Two-Dimensional Kagome Surface States of $R{V}_{6}S{n}_6$ ($R$=Gd,Ho)
• Discovery of charge order and corresponding edge state in kagome magnet FeGe
• Topological Quantum Materials with Kagome Lattice
• Spin-orbit quantum impurity and quantization in a topological magnet
• Enhanced Spin-polarization via Partial Ge1-dimerization as the Driving Force of the 2$\times$2$\times$2 CDW in FeGe
• Chiral phonons in honeycomb sublattice of layered CoSn-like compounds
• Evidence of orbit-selective electronic kagome lattice with planar flat-band in correlated paramagnetic YCr6Ge6
• Large anomalous Hall effect in single crystals of the kagome Weyl ferromagnet Fe${}_3$Sn
• Observation of a Chiral Wave Function in Twofold Degenerate Quadruple Weyl System BaPtGe
• Spin-polarized imaging of the antiferromagnetic structure and field-tunable bound states in kagome magnet FeSn
• Effect of magnetism and phonons on localized carriers in the ferrimagnetic kagome metals GdMn${}_6$Sn${}_6$ and TbMn${}_6$Sn${}_6$
• Giant periodic pseudo-magnetic fields in strained kagome magnet FeSn epitaxial films on SrTiO${}_3$(111) substrate
• Visualizing the Localized Electrons of a Kagome Flat Band
• Charge order in the kagome lattice Holstein model: A hybrid Monte Carlo study
• Visualizing symmetry-breaking electronic orders in epitaxial Kagome magnet FeSn films
• Kagome metals
• Electronic band structures of topological kagome materials
• Phononic drumhead surface state in distorted kagome compound RhPb
• Flat bands and $Z_2$ topological phases in a non-Abelian kagome lattice
• Perspective: imaging atomic step geometry to determine surface terminations of kagome materials and beyond
• Topological magnon in exchange frustration driven incommensurate spin spiral of a kagome lattice YMn${}_6$Sn${}_6$
• Electronic Correlation Effects on Stabilizing a Perfect Kagome Lattice and Ferromagnetic Fluctuation in LaRu${}_3$Si${}_2$
• Charge bond order and s-wave superconductivity in the kagome lattice with electron-phonon coupling and electron-electron interaction
• Robust topological state against magnetic impurities observed in superconductor PbTaSe2
• Non-Abelian line graph: A generalized approach to flat bands