Author:
Li 李 Yun-Xiao 云霄,Xi 西 Wen-Han 文翰,Dong 董 Zhao-Yang 召阳,Yao 姚 Zi-Jian 子健,Yu 于 Shun-Li 顺利,Li 李 Jian-Xin 建新
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 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 d
xy
to the quasi-one-dimensional orbitals d
xz
and d
yz
.
Subject
General Physics and Astronomy