Chern insulators and topological flat bands in cavity-embedded kagome systems

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Hauptverfasser: Goto, Hikaru, Okugawa, Ryo, Tohyama, Takami
Format: Preprint
Veröffentlicht: 2025
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author Goto, Hikaru
Okugawa, Ryo
Tohyama, Takami
author_facet Goto, Hikaru
Okugawa, Ryo
Tohyama, Takami
contents We investigate topological band structures of a kagome system coupled to a circularly polarized cavity mode, using a model based on a muffin-tin potential and quantum light-matter interaction. We show that Chern insulating phases emerge in the cavity-embedded kagome system due to the light-matter interaction that breaks time-reversal symmetry. We also find that a nearly flat band can be topologically nontrivial with a nonzero Chern number. By varying the light-matter interaction, we also reveal that topological phase transitions occur between different Chern insulating phases in the ultrastrong coupling regime. The phase transitions change the sign of the Chern number, switching the direction of the edge current. We demonstrate the existence of topological edge modes in the cavity-embedded kagome Chern insulators by constructing a low-energy effective tight-binding model.
format Preprint
id arxiv_https___arxiv_org_abs_2510_09150
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Chern insulators and topological flat bands in cavity-embedded kagome systems
Goto, Hikaru
Okugawa, Ryo
Tohyama, Takami
Mesoscale and Nanoscale Physics
Optics
Quantum Physics
We investigate topological band structures of a kagome system coupled to a circularly polarized cavity mode, using a model based on a muffin-tin potential and quantum light-matter interaction. We show that Chern insulating phases emerge in the cavity-embedded kagome system due to the light-matter interaction that breaks time-reversal symmetry. We also find that a nearly flat band can be topologically nontrivial with a nonzero Chern number. By varying the light-matter interaction, we also reveal that topological phase transitions occur between different Chern insulating phases in the ultrastrong coupling regime. The phase transitions change the sign of the Chern number, switching the direction of the edge current. We demonstrate the existence of topological edge modes in the cavity-embedded kagome Chern insulators by constructing a low-energy effective tight-binding model.
title Chern insulators and topological flat bands in cavity-embedded kagome systems
topic Mesoscale and Nanoscale Physics
Optics
Quantum Physics
url https://arxiv.org/abs/2510.09150