发表机构
Ludwig-Maximilians-Universität München; Munich Center for Quantum Science and Technology (MCQST)（慕尼黑大学; 慕尼黑量子科学与技术中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究提出隐费米子行列式态作为可扩展变分方法，用于二维三带Emery模型，通过下折叠得到有效单带模型，发现密度辅助跳跃项主导粒子-空穴不对称性，并揭示单带描述需包含多带衍生相互作用。
AI 中文摘要
理解铜氧化物及近年来发现的无限层镍氧化物中高温超导背后的物理机制，一直是凝聚态物理领域的核心挑战。我们建立了神经量子态（NQS），特别是隐费米子行列式态（HFDS），作为一种可扩展的变分方法，用于研究这些材料中铜氧化物和镍氧化物层的三带Emery模型。在宽度为二的几何结构上，我们将HFDS与矩阵乘积态进行基准对比后，研究了多达$10\ imes10$个晶胞（300个格点）的完全二维（2D）系统的基态。我们表征了掺杂剂在动量空间中的分布，并发现了与铜氧化物实验相似的显著电子-空穴二分性。我们进一步通过构造相互作用的Wannier函数，将三带模型下折叠为有效的单带描述。我们考虑了广泛的参数范围——从与铜氧化物相关的电荷转移区域到镍氧化物的Hubbard-Mott区域，以及对已被证明影响临界超导温度的电荷转移能隙的系统性扫描。在所有区域中，有效模型都显著偏离通常的Fermi-Hubbard模型：典型的$U/t$比值增强，一些参数表现出显著的掺杂依赖性，并且存在超出常规Hubbard模型的显著项，最值得注意的是密度辅助跳跃$t_n$。值得注意的是，在所有有效模型中，$t_n$对粒子-空穴不对称性的贡献最大，而非次近邻跳跃贡献。有效参数敏感地依赖于电荷转移能、掺杂和相互作用比值。我们的结果确立了HFDS作为研究二维Emery模型的高效工具，并表明单带描述可能需要由底层多带模型生成的相互作用项。
英文摘要
Understanding the physics underlying high-temperature superconductivity in cuprates and, more recently, infinite-layer nickelates has remained a central challenge in condensed-matter physics. We establish neural quantum states (NQS), specifically Hidden Fermion Determinant States (HFDS), as a scalable variational approach to the three-band Emery model of the copper- and nickel-oxide layers in these materials. After benchmarking HFDS against matrix product states on width-two geometries, we study ground states of fully two-dimensional (2D) systems of up to $10\times10$ unit cells ($300$ sites). We characterize the momentum-space distribution of dopants and find a pronounced electron-hole dichotomy similar to cuprate experiments. We further downfold the three-band model to effective single-band descriptions by constructing interacting Wannier functions. We consider a wide range of parameters -- from the charge-transfer regime relevant to cuprates to the Hubbard-Mott regime of nickelates, as well as systematic scans of the charge-transfer gap that has been demonstrated to impact the critical superconducting temperatures. Across all regimes, the effective model significantly deviates from the usual Fermi-Hubbard model: The typical ratio $U/t$ is enhanced, some parameters experience a significant doping dependence, and sizable terms beyond the conventional Hubbard model are present, most notably a density-assisted hopping $t_n$. Notably, in all effective models, $t_n$ has the largest contribution to particle-hole asymmetry, rather than next-nearest-neighbor hopping contributions. The effective parameters sensitively depend on the charge-transfer energy, doping, and interaction ratios. Our results establish HFDS as an efficient tool for studying the 2D Emery model and demonstrate that single-band descriptions can require interaction terms generated by the underlying multi-band models.
