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arXiv · 1911.03121

Probing the Lattice Anharmonicity of Superconducting YBa$_2$Cu$_3$O$_{7-\delta}$ Via Phonon Harmonics

Alberto Ramos-Alvarez·Nina Fleischmann·Luciana Vidas·Alejandro Fernandez-Rodriguez·Anna Palau·Simon Wall
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Abstract

We examine coherent phonons in a strongly driven sample of optimally-doped high temperature superconductor YBa$_2$Cu$_3$O$_{7-\delta}$. We observe a non-linear lattice response of the 4.5\,THz copper-oxygen vibrational mode at high excitation densities, evidenced by the observation of the phonon third harmonic and indicating the mode is strongly anharmonic. In addition, we observe how high-amplitude phonon vibrations modify the position of the electronic charge transfer resonance. Both of these results have important implications for possible phonon-driven non-equilibrium superconductivity.

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Alberto Ramos-Alvarez, Nina Fleischmann, Luciana Vidas, Alejandro Fernandez-Rodriguez, Anna Palau, Simon Wall. 2019-11-08. Probing the Lattice Anharmonicity of Superconducting YBa$_2$Cu$_3$O$_{7-\delta}$ Via Phonon Harmonics. https://doi.org/10.1103/physrevb.100.184302

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