Spin Triplet Superconductivity in Sr2RuO4 due to Orbital and Spin Fluctuations: Analysis by Two-Dimensional Renormalization Group Theory

Abstract

We study the mechanism of the triplet superconductivity in Sr2RuO4 based on the multiorbital Hubbard model. The electronic states are studied using the renormalization group method. Thanks to the vertex correction (VC) for the susceptibility, which is dropped in the mean-field-level approximations, strong orbital and spin fluctuations at $Q=(2\pi /3,2\pi /3)$ emerge in the quasi one-dimensional Fermi surfaces composed of $d_{xz}$ and $d_{yz}$ orbitals. Due to the cooperation of both fluctuations, we obtain the triplet superconductivity in the $E_u$ representation, in which the superconducting gap is given by the linear combination of $({\Delta }_x(k),{\Delta }_y(k))=(\sin 3k_x,\sin 3k_y)$. These results are confirmed by a diagrammatic calculation called the self-consistent VC method.

5 pages, 4 figures

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Cited by in corpus (8)

• Spin-Orbit-Induced Orbital Excitations in Sr2RuO4 and Ca2RuO4: A Resonant Inelastic X-ray Scattering Study
• Anisotropic spin fluctuations in Sr${}_2$RuO${}_4$: role of spin-orbit coupling and induced strain
• Pauli-paramagnetic effects on mixed state properties in a strongly anisotropic superconductor ---Application to Sr_2_RuO_4_---
• Hexadecapole fluctuation mechanism for s-wave heavy fermion superconductor CeCu2Si2: Interplay between intra- and inter-orbital Cooper pairs
• Identifying possible pairing states in Sr${}_2$RuO${}_4$ by tunneling spectroscopy
• Higher angular momentum pairing states in Sr${}_2$RuO${}_4$ in the presence of longer-range interactions
• Inter-orbital p- and d-wave pairings between $d_{xz/yz}$ and $d_{xy}$ orbitals in Sr${}_2$RuO${}_4$
• A review of some new perspectives on the theory of superconducting Sr${}_2$RuO${}_4$