Generalized Rashba electron-phonon coupling and superconductivity in strontium titanate
SrTiO_{3} is known for its proximity to a ferroelectric phase and for showing an “optimal” doping for superconductivity with a characteristic domelike behavior resembling systems close to a quantum critical point. Several mechanisms have been proposed to link these phenomena, but the abundance of un...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2023-06-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.5.023177 |
| _version_ | 1797210456404787200 |
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| author | Maria N. Gastiasoro Maria Eleonora Temperini Paolo Barone José Lorenzana |
| author_facet | Maria N. Gastiasoro Maria Eleonora Temperini Paolo Barone José Lorenzana |
| author_sort | Maria N. Gastiasoro |
| collection | DOAJ |
| description | SrTiO_{3} is known for its proximity to a ferroelectric phase and for showing an “optimal” doping for superconductivity with a characteristic domelike behavior resembling systems close to a quantum critical point. Several mechanisms have been proposed to link these phenomena, but the abundance of undetermined parameters prevents a definite assessment. Here, we use ab initio computations supplemented with a microscopic model to study the linear coupling between conduction electrons and the ferroelectric soft transverse modes allowed in the presence of spin-orbit coupling. We find a robust Rashba-like coupling, which can become surprisingly strong for particular forms of the polar eigenvector. We characterize this sensitivity for general eigenvectors and, for the particular form deduced by hyper-Raman scattering experiments, we find a Bardeen-Cooper-Schrieffer pairing coupling constant of the right order of magnitude to support superconductivity. The ab initio computations enable us to go beyond the linear-in-momentum conventional Rashba-like interaction and naturally explain the dome behavior including a characteristic asymmetry. The dome is attributed to a momentum-dependent quenching of the angular momentum due to a competition between spin-orbit and hopping energies. The optimum density for having maximum T_{c} results in rather good agreement with experiments without free parameters. These results make the generalized Rashba dynamic coupling to the ferroelectric soft mode a compelling pairing mechanism to understand bulk superconductivity in doped SrTiO_{3}. |
| first_indexed | 2024-04-24T10:10:53Z |
| format | Article |
| id | doaj.art-9ebb2f4c96154df7b6fcd334dddfd8e1 |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:10:53Z |
| publishDate | 2023-06-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-9ebb2f4c96154df7b6fcd334dddfd8e12024-04-12T17:31:54ZengAmerican Physical SocietyPhysical Review Research2643-15642023-06-015202317710.1103/PhysRevResearch.5.023177Generalized Rashba electron-phonon coupling and superconductivity in strontium titanateMaria N. GastiasoroMaria Eleonora TemperiniPaolo BaroneJosé LorenzanaSrTiO_{3} is known for its proximity to a ferroelectric phase and for showing an “optimal” doping for superconductivity with a characteristic domelike behavior resembling systems close to a quantum critical point. Several mechanisms have been proposed to link these phenomena, but the abundance of undetermined parameters prevents a definite assessment. Here, we use ab initio computations supplemented with a microscopic model to study the linear coupling between conduction electrons and the ferroelectric soft transverse modes allowed in the presence of spin-orbit coupling. We find a robust Rashba-like coupling, which can become surprisingly strong for particular forms of the polar eigenvector. We characterize this sensitivity for general eigenvectors and, for the particular form deduced by hyper-Raman scattering experiments, we find a Bardeen-Cooper-Schrieffer pairing coupling constant of the right order of magnitude to support superconductivity. The ab initio computations enable us to go beyond the linear-in-momentum conventional Rashba-like interaction and naturally explain the dome behavior including a characteristic asymmetry. The dome is attributed to a momentum-dependent quenching of the angular momentum due to a competition between spin-orbit and hopping energies. The optimum density for having maximum T_{c} results in rather good agreement with experiments without free parameters. These results make the generalized Rashba dynamic coupling to the ferroelectric soft mode a compelling pairing mechanism to understand bulk superconductivity in doped SrTiO_{3}.http://doi.org/10.1103/PhysRevResearch.5.023177 |
| spellingShingle | Maria N. Gastiasoro Maria Eleonora Temperini Paolo Barone José Lorenzana Generalized Rashba electron-phonon coupling and superconductivity in strontium titanate Physical Review Research |
| title | Generalized Rashba electron-phonon coupling and superconductivity in strontium titanate |
| title_full | Generalized Rashba electron-phonon coupling and superconductivity in strontium titanate |
| title_fullStr | Generalized Rashba electron-phonon coupling and superconductivity in strontium titanate |
| title_full_unstemmed | Generalized Rashba electron-phonon coupling and superconductivity in strontium titanate |
| title_short | Generalized Rashba electron-phonon coupling and superconductivity in strontium titanate |
| title_sort | generalized rashba electron phonon coupling and superconductivity in strontium titanate |
| url | http://doi.org/10.1103/PhysRevResearch.5.023177 |
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