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Exploring charge and spin fluctuations in infinite-layer cuprate SrCuO2 from a phonon perspective

The infinite-layer cuprate A CuO 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 studie...

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Bibliographic Details
Published in:Science China. Physics, mechanics & astronomy mechanics & astronomy, 2024-08, Vol.67 (8), p.287411, Article 287411
Main Authors: Du, Xin, Sun, Pei-Han, Gong, Ben-Chao, Zhang, Jian-Feng, Lu, Zhong-Yi, Liu, Kai
Format: Article
Language:English
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Summary:The infinite-layer cuprate A CuO 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 1 g 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 1 g 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 1 g 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.
ISSN:1674-7348
1869-1927
DOI:10.1007/s11433-024-2388-y