标题： 三维费米面、范霍夫奇点与无限层镍酸盐超导性的增强 显示英文标题

标题： Three-Dimensional Fermi Surface, Van Hove Singularity and Enhancement of Superconductivity in Infinite-Layer Nickelates

摘要： 近期实验揭示了无限层镍酸盐中存在一个具有清晰$k_z$色散关系的三维（3D）费米面，这将其与铜氧化物超导体的对应物区分开来。然而，这种差异对镍酸盐超导性质的影响仍不清楚。 在这里，我们采用结合随机相近似和动力学平均场理论（RPA+DMFT）的方法求解超导性线性间隙方程。我们发现，与类似铜氧化物的二维（2D）单轨道费米面相比，无限层镍酸盐三维费米面上的范霍夫奇点通过驱动系统更接近反铁磁不稳定性，从而显著增强了自旋涨落，进而极大地提升了超导性。 我们的研究结果强调了范霍夫奇点在塑造无限层镍酸盐超导性质中的关键作用，并且更广泛地突出了微妙费米面特征在建模材料特定的非常规超导体中的重要性。 显示英文摘要

摘要： Recent experiments reveal a three-dimensional (3D) Fermi surface with a clear $k_z$ dispersion in infinite-layer nickelates, distinguishing them from their cuprate superconductor counterparts. However, the impact of this difference on the superconducting properties of nickelates remains unclear. Here, we employ a combined random-phase-approximation and dynamical-mean-field-theory (RPA+DMFT) approach to solve the linearized gap equation for superconductivity. We find that, compared to the cuprate-like two-dimensional (2D) single-orbital Fermi surface, the van Hove singularities on the 3D Fermi surface of infinite-layer nickelates strengthen spin fluctuations by driving the system closer to antiferromagnetic instabilities, thereby significantly enhancing superconductivity. Our findings underscore the critical role of the van Hove singularities in shaping the superconducting properties of infinite-layer nickelates and, more broadly, highlight the importance of subtle Fermi surface features in modeling material-specific unconventional superconductors.