Effects of carrier density and interactions on pairing symmetry in a t2g model

By utilizing the fluctuation exchange approximation method,we perform a study on the superconducting pairing symmetry in a t2g three-orbital model on the square lattice.Although the tight-binding parameters of the model are based on Sr2RuO4,we have systematically studied the evolution of superconduc...

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Bibliographic Details
Published in:Chinese physics B 2024-01, Vol.33 (1), p.244-252
Main Authors: Li, Yun-Xiao, Xi, Wen-Han, Dong, Zhao-Yang, Yao, Zi-Jian, Yu, Shun-Li, Li, Jian-Xin
Format: Article
Language:English
Subjects:
Fermi surface
pairing mechanism
three-orbital model
unconventional superconductivity
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Summary:By utilizing the fluctuation exchange approximation method,we perform a study on the superconducting pairing symmetry in a t2g three-orbital model on the square lattice.Although the tight-binding parameters of the model are based on Sr2RuO4,we have systematically studied the evolution of superconducting pairing symmetry with the carrier density and interactions,making our findings relevant to a broader range of material systems.Under a moderate Hund's coupling,we find that spin fluctuations dominate the superconducting pairing,leading to a prevalent spin-singlet pairing with a dx2-y2-wave symmetry for the carrier density within the range of n=1.5-4 per site.By reducing the Hund's coupling,the charge fluctuations are enhanced and play a crucial role in determining the pairing symmetry,leading to a transition of the pairing symmetry from the spin-singlet dx2-y2-wave to the spin-triplet p-wave.Furthermore,we find that the superconducting pairings are orbital dependent.As the carrier density changes from n=4 to n=1.5,the active orbitals for superconducting pairing shift from the quasi-two-dimensional orbital dxy to the quasi-one-dimensional orbitals dxz and dyz.
ISSN:1674-1056
DOI:10.1088/1674-1056/ad1094