Materials-realistic microscopic theoretical descriptions of copper-based superconductors are challenging due to their complex crystal structures combined with strong electron interactions. Here, we demonstrate how density functional theory can accurately describe key structural, electronic, and magnetic properties of the normal state of the prototypical cuprate Bi2Sr2CaCu2O8+x (Bi-2212). We emphasize the importance of accounting for energy-lowering structural distortions, which then allows us to (a) accurately describe the insulating antiferromagnetic (AFM) ground state of the undoped parent compound (in contrast to the metallic state predicted by previous studies); (b) identify numerous low-energy competing spin and charge stripe orders in the hole-overdoped material nearly degenerate in energy with the AFM ordered state, indicating strong spin fluctuations; (c) predict the lowest-energy hole-doped crystal structure including its long-range structural distortions and oxygen dopant positions that match high-resolution scanning transmission electron microscopy measurements; and (d) describe electronic bands near the Fermi energy with flat antinodal dispersions and Fermi surfaces that are in agreement with angle-resolved photoemission spectroscopy (ARPES) measurements and provide a clear explanation for the structural origins of the so-called “shadow bands.” We also show how one must go beyond band theory and include fully dynamic spin fluctuations via a many-body approach when aiming to make quantitative predictions to measure the ARPES spectra in the overdoped material. Finally, regarding spatial inhomogeneity, we show that the local structure at the CuO2 layer, rather than dopant electrostatic effects, modulates the local charge-transfer gaps, local correlation strengths, and by extension the local superconducting gaps. Published by the American Physical Society 2024

中文翻译：

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铜酸盐结构扭曲的第一性原理预测及其对电子结构的影响


铜基超导体的材料真实微观理论描述具有挑战性，因为它们具有复杂的晶体结构以及强电子相互作用。在这里，我们展示了密度泛函理论如何准确描述原型铜酸盐 Bi2Sr2CaCu2O8+x （Bi-2212） 正常状态的关键结构、电子和磁性。我们强调了考虑降低能量的结构扭曲的重要性，这使我们能够 （a） 准确描述未掺杂母体化合物的绝缘反铁磁 （AFM） 基态（与之前研究预测的金属态相反）;（b） 在空穴过掺杂材料中识别出许多低能量竞争性自旋和电荷条带级，几乎以 AFM 有序状态进行能量退化，表明强烈的自旋波动;（c） 预测最低能量的空穴掺杂晶体结构，包括其远程结构畸变和氧掺杂剂位置，与高分辨率扫描透射电子显微镜测量相匹配;（d） 描述费米能量附近的电子带，具有平坦的对结色散和费米表面，这与角度分辨光电子能谱 （ARPES） 测量一致，并为所谓的“影带”的结构起源提供了清晰的解释。我们还展示了在进行定量预测以测量过掺杂材料中的 ARPES 光谱时，如何超越能带理论并通过多体方法包括完全动态的自旋波动。 最后，关于空间不均匀性，我们表明 CuO2 层的局部结构，而不是掺杂剂静电效应，调节了局部电荷转移间隙、局部相关强度，进而调节了局部超导间隙。美国物理学会 2024 年出版