{
  "id": "2009.07263",
  "version": "v1",
  "published": "2020-09-15T17:51:44.000Z",
  "updated": "2020-09-15T17:51:44.000Z",
  "title": "$\\mathbb{Z}_2$ Topologically Obstructed Superconducting Order",
  "authors": [
    "Canon Sun",
    "Yi Li"
  ],
  "categories": [
    "cond-mat.supr-con",
    "cond-mat.str-el"
  ],
  "abstract": "We propose a class of topological superconductivity where the pairing order is $\\mathbb{Z}_2$ topologically obstructed in a time-reversal invariant system in three dimensions. When two Fermi surfaces are related by time-reversal and mirror symmetries, such as those in a $\\mathbb{Z}_2$ 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 $\\mathbb{Z}_2$ topologically obstructed superconductor is constructed based on a doped $\\mathbb{Z}_2$ Dirac semimetal and exhibits nodal gap function. At an open boundary, the system exhibits a time-reversal pair of topologically protected surface states.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-09-15T17:51:44.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "topologically obstructed superconducting order",
      "dirac semimetal",
      "time-reversal invariant system",
      "pairing order",
      "entire fermi surface"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}