Mixed higher-order topology and nodal and nodeless flat band topological phases in a superconducting multiorbital model

Fuente: arXiv
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Auteurs principaux: Arouca, Rodrigo, Nag, Tanay, Black-Schaffer, Annica M.
Format: Preprint
Publié: 2024
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_version_ 1866912005842010112
author Arouca, Rodrigo
Nag, Tanay
Black-Schaffer, Annica M.
author_facet Arouca, Rodrigo
Nag, Tanay
Black-Schaffer, Annica M.
contents We investigate the topological phases that appear in an orbital version of the Benalcazar-Bernevig-Hughes (BBH) model in the presence of conventional spin-singlet $s$-wave superconductivity and with the possibility of tuning an in-plane magnetic field. We chart out the phase diagram by considering different boundary conditions, with the topology of the individual phases further examined by considering both the Wannier and entanglement spectra, as well as the Majorana polarization. For weak to moderate values of magnetic field and superconducting pairing amplitude, we find a second-order topological superconductor phase with eight zero-energy corner modes. Further increasing field or pairing, half of the corner states can be turned into zero-energy edge-localized modes, thus forming a type of hybrid-order phase. Then, we find two different putative first-order topological phases, a nodal and a nodeless phase, both with zero-energy flat bands localized along mirror-symmetric open edges. For the nodal phase, the flat bands are localized between the nodes in reciprocal space, while in the nodeless phase, with its a full bulk gap, the zero-energy boundary flat band spans the whole Brillouin zone.
format Preprint
id arxiv_https___arxiv_org_abs_2402_00556
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Mixed higher-order topology and nodal and nodeless flat band topological phases in a superconducting multiorbital model
Arouca, Rodrigo
Nag, Tanay
Black-Schaffer, Annica M.
Superconductivity
Mesoscale and Nanoscale Physics
Quantum Physics
We investigate the topological phases that appear in an orbital version of the Benalcazar-Bernevig-Hughes (BBH) model in the presence of conventional spin-singlet $s$-wave superconductivity and with the possibility of tuning an in-plane magnetic field. We chart out the phase diagram by considering different boundary conditions, with the topology of the individual phases further examined by considering both the Wannier and entanglement spectra, as well as the Majorana polarization. For weak to moderate values of magnetic field and superconducting pairing amplitude, we find a second-order topological superconductor phase with eight zero-energy corner modes. Further increasing field or pairing, half of the corner states can be turned into zero-energy edge-localized modes, thus forming a type of hybrid-order phase. Then, we find two different putative first-order topological phases, a nodal and a nodeless phase, both with zero-energy flat bands localized along mirror-symmetric open edges. For the nodal phase, the flat bands are localized between the nodes in reciprocal space, while in the nodeless phase, with its a full bulk gap, the zero-energy boundary flat band spans the whole Brillouin zone.
title Mixed higher-order topology and nodal and nodeless flat band topological phases in a superconducting multiorbital model
topic Superconductivity
Mesoscale and Nanoscale Physics
Quantum Physics
url https://arxiv.org/abs/2402.00556