AI 中文总结
研究无限层镍酸盐中电子关联与电子 - 声子相互作用，结合第一性原理计算与涨落交换 - 米格达尔 - 埃利亚什伯格理论，发现自旋涨落产生d波超导，电子 - 声子耦合诱导s波配对，形成s + id超导态，且s波出现依赖载流子密度，解释了实验中空间非均匀超导对称性。
AI 中文摘要
近期对无限层镍酸盐的隧穿测量揭示了空间变化的超导对称性，其微观起源尚不清楚。基于此，我们通过结合第一性原理计算与涨落交换 - 米格达尔 - 埃利亚什伯格理论，研究无限层镍酸盐中电子关联与电子 - 声子相互作用。计算表明自旋涨落在Ni dₓ²₋y²轨道上产生强d波超导性，而电子 - 声子耦合在间隙轨道上诱导s波配对，导致s + id超导态。s波分量的出现强烈依赖载流子密度，如中间电子 - 声子耦合λ = 0.4时，在n = 0.9稳定s + id态，n = 0.8则不然。这些结果表明局部氧缺陷调节局部电子密度并形成具有不同配对对称性的有限尺寸域，为实验中观察到的空间非均匀超导对称性提供了有力解释。
英文摘要
Recent tunneling measurements on infinite-layer nickelates have revealed spatially varying superconducting symmetries, whose microscopic origin remains unclear. Motivated by this observation, we investigate the interplay between electron correlations and electron-phonon interactions in infinite-layer nickelates by combining first-principles calculations with the fluctuation-exchange-Migdal-Eliashberg theory. Our calculations show that spin fluctuations yield robust $d$-wave superconductivity on the Ni $d_{x^2-y^2}$ orbital, whereas electron-phonon coupling induces $s$-wave pairing on an interstitial orbital, leading to an $s+id$ superconducting state. The emergence of the $s$-wave component is strongly carrier-density dependent: an intermediate electron-phonon coupling of $λ=0.4$ stabilizes the $s+id$ state at $n=0.9$ but not at $n=0.8$. These results imply that local oxygen defects tune the local electron density and form finite-size domains with distinct pairing symmetries, offering a compelling explanation for the spatially inhomogeneous superconducting symmetries observed in experiments.
Comments8 pages, 5 figures
