2026-06-03T06:29:27Z https://archive.materialscloud.org/oai2d

oai:materialscloud.org:1872 2023-08-28T10:22:49Z openaire_data community-mcarchive

Esswein, Tobias Spaldin, Nicola A. Esswein, Tobias Spaldin, Nicola A. 2023-08-28 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, λ, of doped KTaO3 along the reciprocal-space high-symmetry directions. Using the Wannier-function approach implemented in the EPW package, we calculate λ 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 Γ 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 λ in the soft optical modes around Γ suggests an importance of ferroelectric soft-mode fluctuations, which is supported by our findings that the mode-resolved λ values are strongly enhanced in polar structures. The inclusion of spin-orbit coupling has negligible influence on our calculated mode-resolved λ values. application/pdf text/markdown application/zip text/plain https://doi.org/10.24435/materialscloud:3t-k3 oai:materialscloud.org:1872 mcid:2023.132 eng Materials Cloud https://doi.org/10.48550/arXiv.2210.14113 https://archive.materialscloud.org/communities/mcarchive https://doi.org/10.24435/materialscloud:83-xf info:eu-repo/semantics/openAccess Creative Commons Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/legalcode electron-phonon coupling KTaO3 ab initio First-principles calculation of electron-phonon coupling in doped KTaO₃ info:eu-repo/semantics/other