Enhanced electron-phonon coupling for charge-density-wave formation in La$_{1.8-x}$Eu$_{0.2}$Sr$_{x}$CuO$_{4+δ}$

Y. Y. Peng; A. A. Husain; M. Mitrano; S. Sun; T. A. Johnson; A. V. Zakrzewski; G. J. MacDougall; A. Barbour; I. Jarrige; V. Bisogni; P. Abbamonte

doi:10.1103/physrevlett.125.097002

arXiv · 1910.05526

Enhanced electron-phonon coupling for charge-density-wave formation in La$_{1.8-x}$Eu$_{0.2}$Sr$_{x}$CuO$_{4+δ}$

Y. Y. Peng·A. A. Husain·M. Mitrano·S. Sun·T. A. Johnson·A. V. Zakrzewski·G. J. MacDougall·A. Barbour·I. Jarrige·V. Bisogni·P. Abbamonte

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Abstract

Charge density wave (CDW) correlations are prevalent in all copper-oxide superconductors. While CDWs in conventional metals are driven by coupling between lattice vibrations and electrons, the role of the electron-phonon coupling (EPC) in cuprate CDWs is strongly debated. Using Cu $L_3$ edge resonant inelastic x-ray scattering (RIXS), we study the CDW and Cu-O bond-stretching phonons in the stripe-ordered cuprate La$_{1.8-x}$Eu$_{0.2}$Sr$_{x}$CuO$_{4+δ}$. We investigate the interplay between charge order and EPC as a function of doping and temperature, and find that the EPC is enhanced in a narrow momentum region around the CDW wave vector. By detuning the incident photon energy from the absorption resonance, we extract an EPC matrix element at the CDW wave vector of $M\simeq$ 0.36 eV, which decreases to $M\simeq$ 0.30 eV at high temperature in the absence of the CDW. Our results suggest a feedback mechanism in which the CDW enhances the EPC which, in turn, further stabilizes the CDW.

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Y. Y. Peng, A. A. Husain, M. Mitrano, S. Sun, T. A. Johnson, A. V. Zakrzewski, G. J. MacDougall, A. Barbour, I. Jarrige, V. Bisogni, P. Abbamonte. 2019-10-12. Enhanced electron-phonon coupling for charge-density-wave formation in La$_{1.8-x}$Eu$_{0.2}$Sr$_{x}$CuO$_{4+δ}$. https://doi.org/10.1103/physrevlett.125.097002

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