Unconventional superconducting pairing symmetry induced by phonons

Abstract

The possibility of non-s-wave superconductivity induced by phonons is investigated using a simple model that is inspired by Sr${}_2$RuO${}_4$. The model assumes a two-dimensional electronic structure, a two-dimensional spin-fluctuation spectrum, and three-dimensional electron-phonon coupling. Taken separately, each interaction favors formation of spin-singlet pairs (of s symmetry for the phonon interaction and d${}_{x^2-y^2}$ symmetry for the spin interaction), but in combination, a variety of more unusual singlet and triplet states are found, depending on the interaction parameters. This may have important implications for Sr${}_2$RuO${}_4$, providing a plausible explanation of how the observed spin fluctuations, which clearly favor d${}_{x^2-y^2}$ pairing, may still be instrumental in creating a superconducting state with a different (e.g., p-wave) symmetry. It also suggests an interpretation of the large isotope effect observed in Sr${}_2$RuO${}_4$. These results indicate that phonons could play a key role in establishing the order-parameter symmetry in Sr${}_2$RuO${}_4$, and possibly in other unconventional superconductors.

6 pages, 5 figures, submitted to Phys. Rev. B

References in corpus (1)

• The Order Parameter for the Superconducting Phases of UPt${}_3$

Cited by in corpus (8)

• Unconventional superconducting pairing by conventional phonons
• Notes on altermagnetism and superconductivity
• Many-body effects on superconductivity mediated by double-magnon processes in altermagnets
• Evidence for singular-phonon-induced nematic superconductivity in a topological superconductor candidate Sr${}_{0.1}$Bi${}_2$Se${}_3$
• Neutron scattering studies on spin fluctuations in Sr${}_2$RuO${}_4$
• Phonon-mediated spin-polarized superconductivity in altermagnets
• Hybrid s-wave superconductivity in CrB${}_2$
• Mechanism for Nodal Topological Superconductivity on PtBi${}_2$ Surface