Zeros of Green functions in topological insulators

This study demonstrates that the zeros of the diagonal components of Green functions are key quantities that can detect noninteracting topological insulators. We show that zeros of the Green functions traverse the band gap in the topological phases. The traverses induce the crosses of zeros, and the...

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Main Authors: Takahiro Misawa, Youhei Yamaji
Format: Article
Language:English
Published: American Physical Society 2022-06-01
Series:Physical Review Research
Online Access:http://doi.org/10.1103/PhysRevResearch.4.023177
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author Takahiro Misawa
Youhei Yamaji
author_facet Takahiro Misawa
Youhei Yamaji
author_sort Takahiro Misawa
collection DOAJ
description This study demonstrates that the zeros of the diagonal components of Green functions are key quantities that can detect noninteracting topological insulators. We show that zeros of the Green functions traverse the band gap in the topological phases. The traverses induce the crosses of zeros, and the zeros' surface in the band gap, analogous to the Fermi surface of metals. By calculating the zeros of the microscopic models, we show the traverses of the zeros universally appear in all six classes of conventional noninteracting topological insulators. By utilizing the eigenvector-eigenvalue identity, which is a recently rediscovered relation in linear algebra, we prove that the traverses of the zeros in the bulk Green functions are guaranteed by the band inversions, which occur in the topological phases. The relevance of the zeros to detecting the exotic topological insulators such as the higher-order topological insulators is also discussed. For the Hamiltonians with the nearest-neighbor hoppings, we also show that the gapless edge state guarantees the zeros' surfaces in the band gap. The analysis demonstrates that the zeros can be used to detect a wide range of topological insulators and thus useful for searching new topological materials.
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spelling doaj.art-5bc8c94c90f44c43af62d35199b975702024-04-12T17:21:30ZengAmerican Physical SocietyPhysical Review Research2643-15642022-06-014202317710.1103/PhysRevResearch.4.023177Zeros of Green functions in topological insulatorsTakahiro MisawaYouhei YamajiThis study demonstrates that the zeros of the diagonal components of Green functions are key quantities that can detect noninteracting topological insulators. We show that zeros of the Green functions traverse the band gap in the topological phases. The traverses induce the crosses of zeros, and the zeros' surface in the band gap, analogous to the Fermi surface of metals. By calculating the zeros of the microscopic models, we show the traverses of the zeros universally appear in all six classes of conventional noninteracting topological insulators. By utilizing the eigenvector-eigenvalue identity, which is a recently rediscovered relation in linear algebra, we prove that the traverses of the zeros in the bulk Green functions are guaranteed by the band inversions, which occur in the topological phases. The relevance of the zeros to detecting the exotic topological insulators such as the higher-order topological insulators is also discussed. For the Hamiltonians with the nearest-neighbor hoppings, we also show that the gapless edge state guarantees the zeros' surfaces in the band gap. The analysis demonstrates that the zeros can be used to detect a wide range of topological insulators and thus useful for searching new topological materials.http://doi.org/10.1103/PhysRevResearch.4.023177
spellingShingle Takahiro Misawa
Youhei Yamaji
Zeros of Green functions in topological insulators
Physical Review Research
title Zeros of Green functions in topological insulators
title_full Zeros of Green functions in topological insulators
title_fullStr Zeros of Green functions in topological insulators
title_full_unstemmed Zeros of Green functions in topological insulators
title_short Zeros of Green functions in topological insulators
title_sort zeros of green functions in topological insulators
url http://doi.org/10.1103/PhysRevResearch.4.023177
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AT youheiyamaji zerosofgreenfunctionsintopologicalinsulators