The recently discovered high-T_c superconductor La₃Ni₂O₇ has sparked renewed interest in unconventional superconductivity. Here we study superconductivity in pressurized La₃Ni₂O₇ based on a bilayer two-orbital t−J model, using the renormalized mean-field theory. Our results reveal a robust s^±-wave pairing driven by the inter-layer \({d}_{{z}^{2}}\) magnetic coupling, which exhibits a transition temperature within the same order of magnitude as the experimentally observed T_c ~ 80 K. We establish a comprehensive superconducting phase diagram in the doping plane. Notably, the La₃Ni₂O₇ under pressure is found to be situated roughly in the optimal doping regime of the phase diagram. When the \({d}_{{x}^{2}-{y}^{2}}\) orbital becomes close to half-filling, d-wave and d + is pairing can emerge from the system. We discuss the interplay between Fermi surface topology and different pairing symmetries. The stability of the s^±-wave pairing against Hund’s coupling and other magnetic exchange couplings is discussed.

最近发现的高温_c超导体La ₃ Ni ₂ O ₇重新激发了人们对非常规超导性的兴趣。在这里，我们使用重正化平均场理论，基于双层双轨道t - J模型研究加压 La ₃ Ni ₂ O ₇中的超导性。我们的结果揭示了由层间磁耦合\({d}_{{z}^{2}}\)驱动的强大的s ^±波配对，其表现出与实验结果相同数量级的转变温度观察到T _c ~ 80 K。我们在掺杂平面上建立了全面的超导相图。值得注意的是，发现加压下的La ₃ Ni ₂ O ₇大致位于相图的最佳掺杂区域。当\({d}_{{x}^{2}-{y}^{2}}\)轨道接近半填充时， d波和d + i配对可以从系统中出现。我们讨论费米表面拓扑和不同配对对称性之间的相互作用。讨论了s ^±波配对对洪德耦合和其他磁交换耦合的稳定性。