Topological flat bands in a kagome lattice multiorbital system

Satoshi Okamoto; Narayan Mohanta; Elbio Dagotto; D. N. Sheng

doi:10.1038/s42005-022-00969-1

Topological flat bands in a kagome lattice multiorbital system

Satoshi Okamoto, Narayan Mohanta, Elbio Dagotto, D. N. Sheng

Materials Theory

Research output: Contribution to journal › Article › peer-review

17 Scopus citations

Abstract

Flat bands and dispersive Dirac bands are known to coexist in the electronic bands in a two-dimensional kagome lattice. Including the relativistic spin-orbit coupling, such systems often exhibit nontrivial band topology, allowing for gapless edge modes between flat bands at several locations in the band structure, and dispersive bands or at the Dirac band crossing. Here, we theoretically demonstrate that a multiorbital system on a kagome lattice is a versatile platform to explore the interplay between nontrivial band topology and electronic interaction. Specifically, here we report that the multiorbital kagome model with the atomic spin–orbit coupling naturally supports topological bands characterized by nonzero Chern numbers C, including a flat band with ∣ C∣ = 1. When such a flat band is 1/3 filled, the non-local repulsive interactions induce a fractional Chern insulating state. We also discuss the possible realization of our findings in real kagome materials.

Original language	English
Article number	198
Journal	Communications Physics
Volume	5
Issue number	1
DOIs	https://doi.org/10.1038/s42005-022-00969-1
State	Published - Dec 2022

Funding

The research of S.O., N.M., and E.D. was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. D.N.S was supported by the U.S. Department of Energy, Office of Basic Energy Sciences under Grant No. DE-FG02-06ER46305 for numerical studies of topological interacting systems. S.O. thanks H. Miao and H. Li for discussions. This research used resources of the Compute and Data Environment for Science (CADES) at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. The research of S.O., N.M., and E.D. was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. D.N.S was supported by the U.S. Department of Energy, Office of Basic Energy Sciences under Grant No. DE-FG02-06ER46305 for numerical studies of topological interacting systems. S.O. thanks H. Miao and H. Li for discussions. This research used resources of the Compute and Data Environment for Science (CADES) at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725. Copyright notice: This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).

Funders	Funder number
CADES	DE-AC05-00OR22725
DOE Public Access Plan
Data Environment for Science
United States Government
U.S. Department of Energy
Office of Science
Basic Energy Sciences	DE-FG02-06ER46305
Division of Materials Sciences and Engineering

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10.1038/s42005-022-00969-1

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Topological flat bands in a kagome lattice multiorbital system

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