{
  "id": "2307.10938",
  "version": "v1",
  "published": "2023-07-20T15:09:26.000Z",
  "updated": "2023-07-20T15:09:26.000Z",
  "title": "Single-Component Superconductivity in UTe$_2$ at Ambient Pressure",
  "authors": [
    "Florian Theuss",
    "Avi Shragai",
    "Gael Grissonnanche",
    "Ian M Hayes",
    "Shanta R Saha",
    "Yun Suk Eo",
    "Alonso Suarez",
    "Tatsuya Shishidou",
    "Nicholas P Butch",
    "Johnpierre Paglione",
    "B. J. Ramshaw"
  ],
  "comment": "19 pages, 11 figures, 5 tables",
  "categories": [
    "cond-mat.supr-con",
    "cond-mat.str-el"
  ],
  "abstract": "The microscopic mechanism of Cooper pairing in a superconductor leaves its fingerprint on the symmetry of the order parameter. UTe$_2$ has been inferred to have a multi-component order parameter that entails exotic effects like time reversal symmetry breaking. However, recent experimental observations in newer-generation samples have raised questions about this interpretation, pointing to the need for a direct experimental probe of the order parameter symmetry. Here, we use pulse echo ultrasound to measure the elastic moduli of samples of UTe$_2$ that exhibit both one and two superconducting transitions. We demonstrate the absence of thermodynamic discontinuities in the shear elastic moduli of both single- and double-transition samples, providing direct evidence that UTe$_2$ has a single-component superconducting order parameter. We further show that the superconductivity is highly sensitive to compression strain along the $a$ and $c$ axes, but insensitive to strain along the $b$ axis. This leads us to suggest a single-component, odd-parity order parameter$-$specifically the B$_{2u}$ order parameter$-$as the most likely order parameter in UTe$_2$.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2023-07-20T15:09:26.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "ambient pressure",
      "single-component superconductivity",
      "order parameter symmetry",
      "direct experimental probe",
      "single-component superconducting order parameter"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 19,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}