Exploring charge and spin fluctuations in infinite-layer cuprate SrCuO_(2)from a phonon perspective  

作　　者：Xin Du Pei-Han Sun Ben-Chao Gong Jian-Feng Zhang Zhong-Yi Lu Kai Liu 

机构地区：[1]Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials&Micro-nano Devices,Renmin University of China,Beijing 100872,China [2]Department of Physics,School of Science,Jiangsu University of Science and Technology,Zhenjiang 212100,China [3]Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [4]Key Laboratory of Quantum State Construction and Manipulation(Ministry of Education),Renmin University of China,Beijing 100872,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2024年第8期159-167,共9页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Key R&D Program of China(Grant Nos.2022YFA1403103,and 2019YFA0308603);the Beijing Natural Science Foundation(Grant No.Z200005);the National Natural Science Foundation of China(Grant Nos.12174443,and 11934020);supported by the National Key R&D Program of China(Grant No.2017YFA0302903);supported by the Project funded by China Postdoctoral Science Foundation(Grant No.2022M723355)。

摘　　要：The infinite-layer cuprate ACu O_(2)(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 SrCuO_(2)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_(2)upon the hole doping.Among all optical phonon modes of SrCuO_(2)in the antiferromagnetic Néel state,only the A_(1g)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 A_(1g)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 T_(c);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 A_(1g)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_(2),which may provide new insights in understanding the cuprate superconductivity.

关 键 词：first-principles calculations cuprate superconductors PHONON charge and spin fluctuations 

分 类 号：O469[理学—凝聚态物理]