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arXiv · 2109.14092

Correlation of strontium anharmonicity with charge-lattice dynamics of the apical oxygens and their coupling to cuprate superconductivity

Steven D. Conradson·Victor Velasco·Marcello B. Silva Neto·Theodore H. Geballe·Chang-Qing Jin·Wen-Min Li·Li-Peng Cao·Andrea Gauzzi·Maarit Karppinen·Andrea Perali·Sandro Wimberger·Alan R. Bishop·Gianguido Baldinozzi·Matthew Latimer·Edmondo Gilioli
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Abstract

Cu K edge X-ray absorption spectra of overdoped superconducting $YSr_2Cu_{2.75}Mo_{0.25}O_{7.54}$ and $Sr_2CuO_{3.3}$ show a remarkably strong correlation of their superconductivity with the local dynamics of their Cu-Sr and Cu-apical-O pairs. This finding that the entire alkaline earth cation-apical O "dielectric" layer has an active role in the unusual electronic properties of cuprates has not been previously considered and has far reaching implications. We develop this idea of a possible role for the apical oxygen charge dynamics via a soft mode of the Sr by applying Kuramoto's synchronization technique to exact diagonalization calculations of two neighboring Cu-apical O pairs bridged by Sr and a planar O atom. These calculations show a first order phase transition to a synchronized state of the Internal Quantum Tunneling Polarons (IQTPs) in which a fraction of the hole originally confined to the apical O atoms of the cluster is transferred onto the planar O. This combination of experimental results and theory demonstrates that the Sr-O dielectric layer of cuprates most likely plays an important role in high temperature superconductivity via its collective charge dynamics that extends into the $CuO_2$ conducting planes.

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Steven D. Conradson, Victor Velasco, Marcello B. Silva Neto, Theodore H. Geballe, Chang-Qing Jin, Wen-Min Li, Li-Peng Cao, Andrea Gauzzi, Maarit Karppinen, Andrea Perali, Sandro Wimberger, Alan R. Bishop, Gianguido Baldinozzi, Matthew Latimer, Edmondo Gilioli. 2022-12-14. Correlation of strontium anharmonicity with charge-lattice dynamics of the apical oxygens and their coupling to cuprate superconductivity. https://arxiv.org/abs/2109.14092

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