Observation of flat bands in breathing kagome semiconductors

ORAL

Abstract

Quantum materials with kagome lattice – comprised of corner-sharing triangles forming a hexagon in the crystal structure - have been studied as the potential playgrounds for exploring the interplay among parameters such as geometry, topology, electronic correlations, magnetic, and charge density orders. Niobium halides, Nb3X8 (X = Cl, Br, I), which are predicted to be two-dimensional magnets, have recently received attention due to their breathing kagome geometry. In this talk, I will discuss the electronic structure of Nb3X8 system revealed by angle-resolved photoemission spectroscopy (ARPES) and first-principles calculations. ARPES results depict the presence of multiple flat and weakly dispersing bands. These bands are well reproduced by the theoretical calculations, which show that they have Nb d character indicating their origin from the Nb atoms forming the breathing kagome plane. These van der Waals materials can be easily thinned down via mechanical exfoliation to the ultrathin limit and such ultrathin samples are stable as shown from the time-dependent Raman spectroscopy measurements at room temperature. These results demonstrate that Nb3X8 system is an excellent material platform for studying breathing kagome induced flat band physics and its connection with magnetism.

*M.N. acknowledges the support from the National Science Foundation (NSF) CAREER Award No. DMR-1847962, the NSF Partnerships for Research and Education in Materials(PREM) Grant No. DMR-2121953, and the Air Force Office of Scientific Research MURI Grant No. FA9550-20-1-0322.

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Publication: PHYSICAL REVIEW B 108, L121404 (2023), Communications Materials volume 3, Article number: 100 (2022)

Presenters

  • Madhab Neupane

    • University of Central Florida
    • Department of Physics, University of Central Florida

Authors

  • Madhab Neupane

    • University of Central Florida
    • Department of Physics, University of Central Florida

  • Sabin Regmi

    • Idaho National Laboratory
    • University of Central Florida
    • Department of Physics, University of Central Florida; Center for Quantum Actinide Science and Technology, Idaho National Laboratory
    • Department of Physics, University of Central Florida; Idaho National Laboratory

  • Anup Pradhan Sakhya

    • University of Central Florida
    • Department of Physics, University of Central Florida

  • Tharindu Warnakulasooriya Fernando

    • University of Washington

  • Yuzhou Zhao

    • University of Washington, Seattle
    • University of Washington

  • Dylan A Jeff

    • University of Central Florida

  • Milo Sprague

    • University of Central Florida
    • Department of Physics, University of Central Florida

  • Favian Gonzalez

    • University of Central Florida

  • Iftakhar Bin Elius

    • University of central Florida
    • University of Central Florida
    • Department of Physics, University of Central Florida

  • Mazharul Islam Mondal

    • University of Central Florida
    • Department of Physics, University of Central Florida

  • Nathan A Valadez

    • University of Central Florida
    • Department of Physics, University of Central Florida

  • Damani Jarrett

    • University of Central Florida

  • Alexis J Agosto-Cuevas

    • University of Central Florida

  • Jihui Yang

    • University of Washington

  • Jiun-Haw Chu

    • University of Washington
    • Department of Physics, University of Washington, Seattle, WA 98105

  • Saiful I Khondaker

    • University of Central Florida

  • Xiaodong Xu

    • University of Washington

  • Ting Cao

    • University of Washington