Brillouin zone folding method for quasiperiodic superconductivity in multilayer systems: application to electronic structure and optical responses

Fuente: arXiv
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Autores principales: Yoshii, Mao, Kitamura, Sota, Morimoto, Takahiro
Formato: Preprint
Publicado: 2023
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author Yoshii, Mao
Kitamura, Sota
Morimoto, Takahiro
author_facet Yoshii, Mao
Kitamura, Sota
Morimoto, Takahiro
contents We construct an efficient momentum space approach to the superconductivity in quasiperiodic multilayer systems. To this end, we extend the Brillouin zone (BZ) folding method to the superconducting (SC) phases by formulating the gap equation in the momentum space representation with the BZ folding. We show that the physical observables in quasiperiodic multilayers are generally given by so-called quasiperiodic functions. Consequently, there appear SC order parameters with finite momenta in the BZ folding method, which corresponds to the spatial fluctuation of the SC order in quasiperiodic multilayers. We also find a systematic way to compute the physical observables in the BZ folding method with a proper normalization condition using the continued fraction approximation. We apply the BZ folding method to a one-dimensional toy model of quasiperiodic superconductors and demonstrate its numerical efficiency compared to the conventional method based on the real space representation with a large system size. We also study a quasiperiodic bilayer system of Rice-Mele model and an s-wave superconductor to demonstrate an efficient computation of optical responses of a quasiperiodic superconductor with inversion symmetry breaking.
format Preprint
id arxiv_https___arxiv_org_abs_2312_09124
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Brillouin zone folding method for quasiperiodic superconductivity in multilayer systems: application to electronic structure and optical responses
Yoshii, Mao
Kitamura, Sota
Morimoto, Takahiro
Superconductivity
Materials Science
We construct an efficient momentum space approach to the superconductivity in quasiperiodic multilayer systems. To this end, we extend the Brillouin zone (BZ) folding method to the superconducting (SC) phases by formulating the gap equation in the momentum space representation with the BZ folding. We show that the physical observables in quasiperiodic multilayers are generally given by so-called quasiperiodic functions. Consequently, there appear SC order parameters with finite momenta in the BZ folding method, which corresponds to the spatial fluctuation of the SC order in quasiperiodic multilayers. We also find a systematic way to compute the physical observables in the BZ folding method with a proper normalization condition using the continued fraction approximation. We apply the BZ folding method to a one-dimensional toy model of quasiperiodic superconductors and demonstrate its numerical efficiency compared to the conventional method based on the real space representation with a large system size. We also study a quasiperiodic bilayer system of Rice-Mele model and an s-wave superconductor to demonstrate an efficient computation of optical responses of a quasiperiodic superconductor with inversion symmetry breaking.
title Brillouin zone folding method for quasiperiodic superconductivity in multilayer systems: application to electronic structure and optical responses
topic Superconductivity
Materials Science
url https://arxiv.org/abs/2312.09124