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