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Main Authors: Filusch, Alexander, Fehske, Holger
Format: Preprint
Published: 2023
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Online Access:https://arxiv.org/abs/2303.17850
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author Filusch, Alexander
Fehske, Holger
author_facet Filusch, Alexander
Fehske, Holger
contents Flat bands can be divided into singular and non-singular ones according to the behavior of their Bloch wave function around band-crossing points in momentum space. We analyze the flat band in the Dice model, which can be tuned by a uniaxial strain in the zigzag direction and a Haldane-type next-nearest neighbor interaction, and derive the topological phase diagram of the modified Haldane-Dice model to obtain all band-gap closings with the central band. When the central band is flat, we determine its compact localized state and classify its behavior at all band-touching points by means of the Hilbert-Schmidt quantum distance. We find that the flat band remains singular for all band-touching points (topological phase transitions) with a maximal quantum distance and give expressions for the resulting non-contractible loop states on the real-space torus.
format Preprint
id arxiv_https___arxiv_org_abs_2303_17850
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Singular flat bands in the modified Haldane-Dice model
Filusch, Alexander
Fehske, Holger
Mesoscale and Nanoscale Physics
Flat bands can be divided into singular and non-singular ones according to the behavior of their Bloch wave function around band-crossing points in momentum space. We analyze the flat band in the Dice model, which can be tuned by a uniaxial strain in the zigzag direction and a Haldane-type next-nearest neighbor interaction, and derive the topological phase diagram of the modified Haldane-Dice model to obtain all band-gap closings with the central band. When the central band is flat, we determine its compact localized state and classify its behavior at all band-touching points by means of the Hilbert-Schmidt quantum distance. We find that the flat band remains singular for all band-touching points (topological phase transitions) with a maximal quantum distance and give expressions for the resulting non-contractible loop states on the real-space torus.
title Singular flat bands in the modified Haldane-Dice model
topic Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2303.17850