The mysterious oddness of strontium ruthenate's superconducting state: Strong electronic correlations and spin-orbit coupling in multi-orbital systems

ORAL  · Invited

Abstract

Recent experimental improvements have established key properties of the superconducting order parameter of strontium ruthenate, yet some of those give seemingly different pictures that are challenging to reconcile in a single theory [1, 2]. First reviewing these latest developments, we then present a numerical framework to study potential leading instabilities based on first-principles approaches and strong electronic correlations [3, 4]. The results highlight the importance of spin-orbit coupling in entangling electronic quantum numbers, yielding rich and complex order parameters. They suggest a rare type of order dominated by odd-frequency pairing as a prime candidate, which is also found using frequency-dependent linear response theory within dynamical mean-field theory. We discuss observable signatures in specific heat associated with these leading states and develop a static interpretation of odd-frequency pairings.

[1] Li et al., Proceedings of the National Academy of Sciences 118, e2020492118 (2021).

[2] Grinenko et al., Nature Physics 17, 748 (2021).

[3] Gingras et al., Physical Review Letters 123, 217005 (2019).

[4] Gingras et al., Physical Review B 106, 064513 (2022).

*This work has been supported by the Fonds de Recherche du Québec-Nature et Technologie (FRQNT), the Hydro-Québec fellowship, and the Université de Montréal, the Research Chair in the Theory of Quantum Materials, the Canada First Research Excellence Fund, the Natural Sciences and Engineering Research Council of Canada (NSERC). Simulations were performed on computers provided by the Canada Foundation for Innovation, the Ministère de l'Éducation, du Loisir et du Sport (MELS) (Québec), Calcul Québec, Compute Canada and the Flatiron Institute. The Flatiron Institute is a division of the Simons Foundation.

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Publication: Published:
O. Gingras et al., Physical Review Letters 123, 217005 (2019).
O. Gingras et al., Physical Review B 106, 064513 (2022).

Planned:
O. Gingras, O. Parcollet and A. Georges, Investigating frequency-dependent superconducting states using linear response theory within
dynamical mean-field theory.
O. Gingras, A. Georges, Toy model for odd-frequency superconductivity.
M.-A. Gauthier, A.-M. S. Tremblay and O. Gingras, Specific heat calculations for multi-orbital superconducting states.

Presenters

  • Olivier Gingras

    • Center for Computational Quantum Physics, Flatiron Institute

Authors

  • Olivier Gingras

    • Center for Computational Quantum Physics, Flatiron Institute