Publication date: Nov 04, 2022
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] 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 is largest in the [001] direction and weakest in the [111] direction. This is in contrast to the experimentally measured critical temperatures, which are highest for the (111) plane, pointing to a non-BCS character of the superconductivity. The strong localization of λ in the soft optical modes around Γ suggests an importance of ferroelectric soft-mode fluctuations.
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File name | Size | Description |
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README.txt
MD5md5:f4cb8a545b1067d7c14f012a81da4827
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1.8 KiB | README |
materialscloud_KTO_EPW.zip
MD5md5:328ecd4ef414ddb3d8fcfa35ed19a5f5
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429.4 KiB | zip file containing all input files |
2023.132 (version v3) | Aug 28, 2023 | DOI10.24435/materialscloud:3t-k3 |
2023.105 (version v2) | Jul 06, 2023 | DOI10.24435/materialscloud:sn-xs |
2022.136 (version v1) [This version] | Nov 04, 2022 | DOI10.24435/materialscloud:7z-wx |