Abstract
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.
基金项目
National Key Research and Development Program of China(2021YFA1400400)
National Natural Science Foundation of China(92165205)
National Natural Science Foundation of China(12074175)
National Natural Science Foundation of China(12374137)
万方数据