First-principles calculation of electron-phonon coupling in doped KTaO3 [version 1; peer review: 1 approved, 2 approved with reservations]
Background: 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. Methods: Using the Wannier...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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F1000 Research Ltd
2023-10-01
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| Series: | Open Research Europe |
| Subjects: | |
| Online Access: | https://open-research-europe.ec.europa.eu/articles/3-177/v1 |
| _version_ | 1797386836029472768 |
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| author | Nicola A. Spaldin Tobias Esswein |
| author_facet | Nicola A. Spaldin Tobias Esswein |
| author_sort | Nicola A. Spaldin |
| collection | DOAJ |
| description | Background: 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. Methods: 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. Results: 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. Conclusions: 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. |
| first_indexed | 2024-03-08T22:15:10Z |
| format | Article |
| id | doaj.art-4d487b27ba8047d89194a43702c5def7 |
| institution | Directory Open Access Journal |
| issn | 2732-5121 |
| language | English |
| last_indexed | 2024-03-08T22:15:10Z |
| publishDate | 2023-10-01 |
| publisher | F1000 Research Ltd |
| record_format | Article |
| series | Open Research Europe |
| spelling | doaj.art-4d487b27ba8047d89194a43702c5def72023-12-19T01:00:00ZengF1000 Research LtdOpen Research Europe2732-51212023-10-01317609First-principles calculation of electron-phonon coupling in doped KTaO3 [version 1; peer review: 1 approved, 2 approved with reservations]Nicola A. Spaldin0https://orcid.org/0000-0003-0709-9499Tobias Esswein1https://orcid.org/0000-0001-8061-9687Department of Materials, ETH Zurich, Zürich, Zurich, 8093, SwitzerlandDepartment of Materials, ETH Zurich, Zürich, Zurich, 8093, SwitzerlandBackground: 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. Methods: 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. Results: 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. Conclusions: 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.https://open-research-europe.ec.europa.eu/articles/3-177/v1KTaO3 electron-phonon coupling polarization spin-orbit couplingeng |
| spellingShingle | Nicola A. Spaldin Tobias Esswein First-principles calculation of electron-phonon coupling in doped KTaO3 [version 1; peer review: 1 approved, 2 approved with reservations] Open Research Europe KTaO3 electron-phonon coupling polarization spin-orbit coupling eng |
| title | First-principles calculation of electron-phonon coupling in doped KTaO3 [version 1; peer review: 1 approved, 2 approved with reservations] |
| title_full | First-principles calculation of electron-phonon coupling in doped KTaO3 [version 1; peer review: 1 approved, 2 approved with reservations] |
| title_fullStr | First-principles calculation of electron-phonon coupling in doped KTaO3 [version 1; peer review: 1 approved, 2 approved with reservations] |
| title_full_unstemmed | First-principles calculation of electron-phonon coupling in doped KTaO3 [version 1; peer review: 1 approved, 2 approved with reservations] |
| title_short | First-principles calculation of electron-phonon coupling in doped KTaO3 [version 1; peer review: 1 approved, 2 approved with reservations] |
| title_sort | first principles calculation of electron phonon coupling in doped ktao3 version 1 peer review 1 approved 2 approved with reservations |
| topic | KTaO3 electron-phonon coupling polarization spin-orbit coupling eng |
| url | https://open-research-europe.ec.europa.eu/articles/3-177/v1 |
| work_keys_str_mv | AT nicolaaspaldin firstprinciplescalculationofelectronphononcouplingindopedktao3version1peerreview1approved2approvedwithreservations AT tobiasesswein firstprinciplescalculationofelectronphononcouplingindopedktao3version1peerreview1approved2approvedwithreservations |