Topological flat bands in the 3<i>d</i> transition metal-based kagome lattices

ORAL

Abstract

Electronic flat bands in momentum space, arising from strong localization of electrons in real space, are an ideal stage to realize strong correlation phenomena as highlighted by the recent example of twisted-bilayer graphene. In certain lattice systems, electronic flat bands with nontrivial topology may naturally arise from the combination of geometrical frustration, spin-orbit coupling, and reduced dimensionality, while their experimental realization has been elusive so far. Here, we report the observation of topological flat bands in series of 3d transition metal-based kagome compounds. Using angle-resolved photoemission spectroscopy, we directly show how the dispersion of the flat bands is strongly quenched along all three momentum directions. Spin-orbit coupling opens a large gap at the quadratic band touching point between the Dirac and flat bands, endowing a nonzero Z2 topological invariant to the flat band. Our observation opens a promising route to engineer novel emergent phases at the crossroad between strong correlated and topological materials.

*This work was supported by the STC Center for Integrated Quantum Materials, NSF Grant No.DMR-1231319, Gordon and Betty Moore Foundation EPiQS Initiative, Grant No. GBMF3848, and ARO Grant No.W911NF-16-1-0034.

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Presenters

  • Min Gu Kang

    • Massachusetts Institute of Technology MIT
    • Massachusetts Institute of Technology
    • Department of Physics, Massachusetts Institute of Technology
    • Physics, MIT

Authors

  • Min Gu Kang

    • Massachusetts Institute of Technology MIT
    • Massachusetts Institute of Technology
    • Department of Physics, Massachusetts Institute of Technology
    • Physics, MIT

  • Shiang Fang

    • Harvard University
    • Department of Physics and Astronomy, Rutgers University
    • Harvard
    • Department of Physics, Harvard University
    • Physics, Harvard University

  • Linda Ye

    • Massachusetts Institute of Technology
    • Massachusetts Institute of Technology MIT
    • Department of Physics, Massachusetts Institute of Technology
    • Physics, MIT

  • Hoi Chun Po

    • Massachusetts Institute of Technology
    • MIT
    • Department of Physics, MIT
    • Department of Physics, Massachusetts Institute of Technology
    • Massachusetts Institute of Technology MIT

  • Jonathan Denlinger

    • Lawrence Berkeley National Laboratory
    • Advanced Light Source, Lawrence Berkeley National Laboratory
    • Advanced Light Source, Lawrence Berkeley National Lab
    • Advanced Light Source
    • Advanced Light Source, E. O. Lawrence Berkeley National Laboratory

  • Chris Jozwiak

    • Advanced Light Source, Lawrence Berkeley National Lab
    • Lawrence Berkeley National Laboratory
    • Advanced Light Source, Lawrence Berkeley National Laboratory
    • Advanced Light Source, E. O. Lawrence Berkeley National Laboratory
    • ALS, Lawrence Berkeley National Lab
    • Advanced Light Source

  • Aaron Bostwick

    • Advanced Light Source, Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory
    • Advanced Light Source, Lawrence Berkeley National Lab
    • Advanced Light Source, E. O. Lawrence Berkeley National Laboratory
    • ALS, Lawrence Berkeley National Lab
    • Advanced Light Source

  • Eli Rotenberg

    • Advanced Light Source, Lawrence Berkeley National Laboratory
    • Lawrence Berkeley National Laboratory
    • Advanced Light Source, Lawrence Berkeley National Lab
    • Advanced Light Source, E. O. Lawrence Berkeley National Laboratory
    • ALS, Lawrence Berkeley National Lab
    • Advanced Light Source

  • Efthimios Kaxiras

    • Harvard University
    • Department of Physics, Harvard University

  • Joseph G Checkelsky

    • Department of Physics, Massachusetts Institute of Technology
    • Department of Physics, Massachusetts Institute of Technology MIT
    • Massachusetts Institute of Technology
    • Massachusetts Institute of Technology MIT
    • Physics, MIT

  • Riccardo Comin

    • Massachusetts Institute of Technology MIT
    • Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
    • Massachusetts Institute of Technology
    • Department of Physics, Massachusetts Institute of Technology
    • Physics, MIT