Xin Du, Pei-Han Sun, Ben-Chao Gong, Jian-Feng Zhang, Zhong-Yi Lu, Kai Liu
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Among all optical phonon modes of SrCuO<sub>2</sub> in the antiferromagnetic Néel state, only the <i>A</i><sub>1<i>g</i></sub> mode that involves the full-breathing O vibrations along the Cu-O bonds can cause significant fluctuations of local magnetic moments on O atoms and dramatic charge redistributions between Cu and O atoms. Notably, due to the atomic displacements of the <i>A</i><sub>1<i>g</i></sub> mode, both the charge fluctuations on Cu and the electrical dipoles on O show a dome-like evolution with increasing hole doping, quite similar to the experimentally observed behavior of the superconducting <i>T</i><sub><i>c</i></sub>; in comparison, the fluctuations of local magnetic moments on O display a monotonic enhancement along with the hole doping. Further analyses indicate that around the optimal doping, there exists a large softening in the frequency of the <i>A</i><sub>1<i>g</i></sub> phonon mode and a van Hove singularity in the electronic structure close to the Fermi level, suggesting potential electron-phonon coupling. Our work reveals the important role of the full-breathing O phonon mode playing in the infinite-layer SrCuO<sub>2</sub>, which may provide new insights in understanding the cuprate superconductivity.</p></div>","PeriodicalId":774,"journal":{"name":"Science China Physics, Mechanics & Astronomy","volume":null,"pages":null},"PeriodicalIF":6.4000,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Exploring charge and spin fluctuations in infinite-layer cuprate SrCuO2 from a phonon perspective\",\"authors\":\"Xin Du, Pei-Han Sun, Ben-Chao Gong, Jian-Feng Zhang, Zhong-Yi Lu, Kai Liu\",\"doi\":\"10.1007/s11433-024-2388-y\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>The infinite-layer cuprate <i>A</i>CuO<sub>2</sub> (<i>A</i> = Ca, Sr, Ba) possesses the simplest crystal structure among numerous cuprate superconductors and can serve as a prototypical system to explore the unconventional superconductivity. Based on the first-principles electronic structure calculations, we have studied the electronic and magnetic properties of the infinite-layer cuprate SrCuO<sub>2</sub> from a phonon perspective. We find that interesting fluctuations of charges, electrical dipoles, and local magnetic moments can be induced by the atomic displacements of phonon modes in SrCuO<sub>2</sub> upon the hole doping. Among all optical phonon modes of SrCuO<sub>2</sub> in the antiferromagnetic Néel state, only the <i>A</i><sub>1<i>g</i></sub> mode that involves the full-breathing O vibrations along the Cu-O bonds can cause significant fluctuations of local magnetic moments on O atoms and dramatic charge redistributions between Cu and O atoms. 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引用次数: 0
摘要
无限层杯状超导体 ACuO2(A = Ca、Sr、Ba)是众多杯状超导体中晶体结构最简单的一种,可以作为探索非常规超导电性的原型体系。在第一原理电子结构计算的基础上,我们从声子的角度研究了无限层杯状 SrCuO2 的电子和磁性能。我们发现,在掺入空穴后,SrCuO2 中声子模式的原子位移会引起电荷、电偶极子和局部磁矩的有趣波动。在反铁磁奈尔态 SrCuO2 的所有光学声子模式中,只有涉及沿 Cu-O 键全息 O 振动的 A1g 模式能引起 O 原子上局部磁矩的显著波动以及 Cu 和 O 原子间电荷的剧烈再分布。值得注意的是,由于 A1g 模式的原子位移,随着空穴掺杂量的增加,Cu 原子上的电荷波动和 O 原子上的电偶极子都呈现出圆顶状演变,这与实验观测到的超导 Tc 的行为非常相似;相比之下,O 原子上的局部磁矩波动则随着空穴掺杂量的增加而呈现出单调增强。进一步的分析表明,在最佳掺杂度附近,A1g 声子模式的频率有很大的软化,在费米水平附近的电子结构中出现了范霍夫奇点,这表明潜在的电子-声子耦合。我们的研究揭示了全呼吸 O 声子模式在无限层 SrCuO2 中的重要作用,这可能为理解杯状超导提供新的见解。
Exploring charge and spin fluctuations in infinite-layer cuprate SrCuO2 from a phonon perspective
The infinite-layer cuprate ACuO2 (A = Ca, Sr, Ba) possesses the simplest crystal structure among numerous cuprate superconductors and can serve as a prototypical system to explore the unconventional superconductivity. Based on the first-principles electronic structure calculations, we have studied the electronic and magnetic properties of the infinite-layer cuprate SrCuO2 from a phonon perspective. We find that interesting fluctuations of charges, electrical dipoles, and local magnetic moments can be induced by the atomic displacements of phonon modes in SrCuO2 upon the hole doping. Among all optical phonon modes of SrCuO2 in the antiferromagnetic Néel state, only the A1g mode that involves the full-breathing O vibrations along the Cu-O bonds can cause significant fluctuations of local magnetic moments on O atoms and dramatic charge redistributions between Cu and O atoms. Notably, due to the atomic displacements of the A1g mode, both the charge fluctuations on Cu and the electrical dipoles on O show a dome-like evolution with increasing hole doping, quite similar to the experimentally observed behavior of the superconducting Tc; in comparison, the fluctuations of local magnetic moments on O display a monotonic enhancement along with the hole doping. Further analyses indicate that around the optimal doping, there exists a large softening in the frequency of the A1g phonon mode and a van Hove singularity in the electronic structure close to the Fermi level, suggesting potential electron-phonon coupling. Our work reveals the important role of the full-breathing O phonon mode playing in the infinite-layer SrCuO2, which may provide new insights in understanding the cuprate superconductivity.
期刊介绍:
Science China Physics, Mechanics & Astronomy, an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China, and published by Science China Press, is committed to publishing high-quality, original results in both basic and applied research.
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