ℤ₂ Topologically Obstructed Superconducting Order

2020/09/15 by Canon Sun, Yi Li, Sun, Canon +1
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Graphene research and applications #Quantum, superfluid, helium dynamics #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con) #Topological Materials and Phenomena #cond-mat.str-el #cond-mat.supr-con

paper · pdf · doi:10.48550/arxiv.2009.07263

8 pages, 6 figures

openalex publication_date 2020/09/15 · arxiv created 2020/11/13 · arxiv updated 2020/11/17 · openalex created_date 2021/03/01 · openalex updated_date 2026/07/28

Abstract

We propose a class of topological superconductivity in which the pairing order is ℤ₂ topologically obstructed in a three-dimensional time-reversal invariant system. When two Fermi surfaces are related by time-reversal and mirror symmetries, such as those in a ℤ₂ Dirac semimetal, the inter-Fermi-surface pairing in the weak-coupling regime inherits the band topological obstruction. As a result, the pairing order cannot be well-defined over the entire Fermi surface and forms a time-reversal invariant generalization of U(1) monopole harmonic pairing. A tight-binding model of the ℤ₂ topologically obstructed superconductor is constructed based on a doped ℤ₂ Dirac semimetal and exhibits nodal pairings. At an open boundary, the system exhibits a time-reversal pair of topologically protected surface states.

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