摘要
By utilizing the fluctuation exchange approximation method,we perform a study on the superconducting pairing symmetry in a t_(2g) three-orbital model on the square lattice.Although the tight-binding parameters of the model are based on Sr_(2)RuO_(4),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 d_(x^(2)-y^(2))-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 d_(x^(2)-y^(2))-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 d_(xz) and d_(yz).
作者
李云霄
西文翰
董召阳
姚子健
于顺利
李建新
Yun-Xiao Li;Wen-Han Xi;Zhao-Yang Dong;Zi-Jian Yao;Shun-Li Yu;Jian-Xin Li(National Laboratory of Solid State Microstructures and Department of Physics,Nanjing University,Nanjing 210093,China;Nanjing University of Science and Technology,Nanjing 210094,China;Department of Physics,Nanjing Normal University,Nanjing 210023,China;Collaborative Innovation Center of Advanced Microstructures,Nanjing University,Nanjing 210093,China)
基金
Project supported by the National Key Research and Development Program of China (Grant No.2021YFA1400400)
the National Natural Science Foundation of China (Grant Nos.92165205,12074175,and 12374137)。