Superconductivity in Correlated Multi-Orbital Systems with Spin-Orbit Coupling: Coexistence of Even- and Odd-Frequency Pairing and the Case of Strontium Ruthenate
| Autor: | Gingras, Olivier, Allaglo, Nikita, Nourafkan, Reza, Côté, Michel, Tremblay, André-Marie S. |
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| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 106, 064513 (2022) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.106.064513 |
| Popis: | The superconducting order parameter of strontium ruthenate is the center of a lasting puzzle calling for theoretical studies that include the seldom-considered effects of spin-orbit coupling and the frequency-dependence of the order parameters. Here we generalize the frequency-dependent theory of superconductivity mediated by spin and charge fluctuations to include spin-orbit coupling in multi-orbital systems and we characterize the superconducting states using the spin-parity-orbital-time $SPOT$ quantum numbers, group theory, and phase distributions in the complex plane. We derive a pseudospin formulation that maps the inter-pseudospin sector of the normal state Eliashberg equation to a pseudospin-diagonal one. Possible superconducting order parameters for strontium ruthenate are obtained starting from a realistic density-functional-theory normal state. We find that spin-orbit coupling leads to ubiquitous entanglement of spin and orbital quantum numbers, along with notable mixing between even- and odd-frequency correlations. We propose a phase diagram obtained from the temperature dependence of the leading and subleading symmetries in the pseudospin-orbital basis. An accidental degeneracy between leading inter-pseudospin symmetries in strontium ruthenate, B$_{1g}^+$ and A$_{2g}^-$, could resolve apparent experimental contradictions. Comment: 30 pages, 17 figures |
| Databáze: | arXiv |
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