Weyl superconductivity and quasiperiodic Majorana arcs in quasicrystals

Fuente: arXiv
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Hauptverfasser: Hori, Masahiro, Okugawa, Ryo, Tanaka, K., Tohyama, Takami
Format: Preprint
Veröffentlicht: 2024
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author Hori, Masahiro
Okugawa, Ryo
Tanaka, K.
Tohyama, Takami
author_facet Hori, Masahiro
Okugawa, Ryo
Tanaka, K.
Tohyama, Takami
contents Weyl superconductivity is a topological phase in three-dimensional crystals in which the Weyl equation describes quasiparticle excitation near band-touching points in momentum space called Weyl nodes. For quasicrystals which lack translational symmetry, a theory of Weyl superconductivity has not been established, in spite of recent extensive studies on quasicrystalline topological phases. Here, we demonstrate the occurrence of quasicrystalline Weyl superconductivity by extending the definition of Weyl superconductivity to periodically stacked, two-dimensional superconducting quasicrystals. We identify quasicrystalline Weyl nodes -- topologically protected point nodes in one-dimensional momentum space corresponding to the stacking direction -- in terms of a topological invariant given by a change in the Bott index in quasicrystalline layers. We find that these Weyl nodes exist in pairs and that Majorana zero-energy modes protected by the nonzero Bott index between a pair of quasicrystalline Weyl nodes appear on surfaces. These Majorana zero modes form an infinite number of arcs in momentum space, densely and quasiperiodically distributed as a function of momentum in the direction of surfaces within each quasicrystalline layer. In Ammann-Beenker (Penrose) quasicrystals, the quasiperiodicity of Majorana arcs is governed by the silver (golden) ratio associated with the quasicrystalline structure.
format Preprint
id arxiv_https___arxiv_org_abs_2403_08889
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Weyl superconductivity and quasiperiodic Majorana arcs in quasicrystals
Hori, Masahiro
Okugawa, Ryo
Tanaka, K.
Tohyama, Takami
Superconductivity
Weyl superconductivity is a topological phase in three-dimensional crystals in which the Weyl equation describes quasiparticle excitation near band-touching points in momentum space called Weyl nodes. For quasicrystals which lack translational symmetry, a theory of Weyl superconductivity has not been established, in spite of recent extensive studies on quasicrystalline topological phases. Here, we demonstrate the occurrence of quasicrystalline Weyl superconductivity by extending the definition of Weyl superconductivity to periodically stacked, two-dimensional superconducting quasicrystals. We identify quasicrystalline Weyl nodes -- topologically protected point nodes in one-dimensional momentum space corresponding to the stacking direction -- in terms of a topological invariant given by a change in the Bott index in quasicrystalline layers. We find that these Weyl nodes exist in pairs and that Majorana zero-energy modes protected by the nonzero Bott index between a pair of quasicrystalline Weyl nodes appear on surfaces. These Majorana zero modes form an infinite number of arcs in momentum space, densely and quasiperiodically distributed as a function of momentum in the direction of surfaces within each quasicrystalline layer. In Ammann-Beenker (Penrose) quasicrystals, the quasiperiodicity of Majorana arcs is governed by the silver (golden) ratio associated with the quasicrystalline structure.
title Weyl superconductivity and quasiperiodic Majorana arcs in quasicrystals
topic Superconductivity
url https://arxiv.org/abs/2403.08889