First-principles calculation of electron-phonon coupling in doped KTaO₃
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{
"updated": "2023-08-28T08:22:49.766582+00:00",
"created": "2023-08-26T13:55:19.335221+00:00",
"id": "1872",
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"contributors": [
{
"givennames": "Tobias",
"affiliations": [
"Materials Theory, Department of Materials, ETH Z\u00fcrich, Wolfgang-Pauli-Strasse 27, 8093 Z\u00fcrich, Switzerland"
],
"familyname": "Esswein",
"email": "tobias.esswein@mat.ethz.ch"
},
{
"givennames": "Nicola A.",
"affiliations": [
"Materials Theory, Department of Materials, ETH Z\u00fcrich, Wolfgang-Pauli-Strasse 27, 8093 Z\u00fcrich, Switzerland"
],
"familyname": "Spaldin",
"email": "nicola.spaldin@mat.ethz.ch"
}
],
"status": "published",
"keywords": [
"electron-phonon coupling",
"KTaO3",
"ab initio"
],
"id": "1872",
"version": 3,
"license_addendum": null,
"conceptrecid": "1468",
"title": "First-principles calculation of electron-phonon coupling in doped KTaO\u2083",
"doi": "10.24435/materialscloud:3t-k3",
"is_last": true,
"publication_date": "Aug 28, 2023, 10:22:49",
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"license": "Creative Commons Attribution 4.0 International",
"edited_by": 576,
"description": "Motivated by the recent experimental discovery of strongly surface-plane-dependent superconductivity at surfaces of KTaO3 single crystals, we calculate the electron-phonon coupling strength, \u03bb, of doped KTaO3 along the reciprocal-space high-symmetry directions. Using the Wannier-function approach implemented in the EPW package, we calculate \u03bb across the experimentally covered doping range and compare its mode-resolved distribution along the [001], [110] and [111] reciprocal-space directions. We find that the electron-phonon coupling is strongest in the optical modes around the \u0393 point, with some distribution to higher k values in the [001] direction. The electron-phonon coupling strength as a function of doping has a dome-like shape in all three directions and its integrated total is largest in the [001] direction and smallest in the [111] direction, in contrast to the experimentally measured trends in critical temperatures. This disagreement points to a non-BCS character of the superconductivity. Instead, the strong localization of \u03bb in the soft optical modes around \u0393 suggests an importance of ferroelectric soft-mode fluctuations, which is supported by our findings that the mode-resolved \u03bb values are strongly enhanced in polar structures. The inclusion of spin-orbit coupling has negligible influence on our calculated mode-resolved \u03bb values.",
"references": [
{
"url": "https://arxiv.org/abs/2210.14113",
"doi": "https://doi.org/10.48550/arXiv.2210.14113",
"type": "Preprint",
"citation": "T. Esswein, N. A. Spaldin, arXiv 2210.14113 (2022)."
}
]
},
"revision": 2
}