Identifying topological excitonic insulators via bulk-edge correspondence

Fuente: arXiv
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Main Authors: Qu, Hongwei, Zhang, Zeying, Li, Yuanchang
Format: Preprint
Published: 2024
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author Qu, Hongwei
Zhang, Zeying
Li, Yuanchang
author_facet Qu, Hongwei
Zhang, Zeying
Li, Yuanchang
contents Excitonic insulator remains elusive and there has been a lack of reliable identification methods. In this work, we demonstrate the promise of topological excitonic insulators for identification due to their unique bulk-edge correspondence, as illustrated by the LiFe$X$ ($X$ = S, Se, and Te) family. First-principles Bethe-Salpeter equation calculations reveal excitonic instabilities in these spin-orbit coupling quantum anomalous Hall insulators. Effective Hamiltonian analyses indicate that spontaneous exciton condensation does not disrupt the gapless edge state but reconstructs the bulk-gap to be almost independent of the spin-orbit coupling strength. This change in the bulk-edge correspondence can be experimentally inspected by angle-resolved photoelectron spectroscopy or electron compressibility measurements, providing observational evidence for the identification of topological excitonic insulators. Moreover, exciton condensation raises the critical temperature of the topological nontrivial phase above room temperature.
format Preprint
id arxiv_https___arxiv_org_abs_2412_14600
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Identifying topological excitonic insulators via bulk-edge correspondence
Qu, Hongwei
Zhang, Zeying
Li, Yuanchang
Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
Excitonic insulator remains elusive and there has been a lack of reliable identification methods. In this work, we demonstrate the promise of topological excitonic insulators for identification due to their unique bulk-edge correspondence, as illustrated by the LiFe$X$ ($X$ = S, Se, and Te) family. First-principles Bethe-Salpeter equation calculations reveal excitonic instabilities in these spin-orbit coupling quantum anomalous Hall insulators. Effective Hamiltonian analyses indicate that spontaneous exciton condensation does not disrupt the gapless edge state but reconstructs the bulk-gap to be almost independent of the spin-orbit coupling strength. This change in the bulk-edge correspondence can be experimentally inspected by angle-resolved photoelectron spectroscopy or electron compressibility measurements, providing observational evidence for the identification of topological excitonic insulators. Moreover, exciton condensation raises the critical temperature of the topological nontrivial phase above room temperature.
title Identifying topological excitonic insulators via bulk-edge correspondence
topic Strongly Correlated Electrons
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2412.14600