The influence of phonon symmetry and electronic structure on the electron-phonon coupling momentum dependence in cuprates
Journal article, 2026
The experimental determination of the magnitude and momentum dependence of electron-phonon coupling (EPC) is an outstanding problem in condensed matter physics. The intensity of phonon peaks in Resonant Inelastic X-ray Scattering (RIXS) spectra can be related to the underlying EPC strength under significant approximations whose validity deserves careful verification. We measured the Cu L3 RIXS phonon intensity as a function of incident photon energy and momentum transfer in several layered cuprates. For CaCuO2, La2−xSrxCuO4+δ, and YBa2Cu3O6, using a generally accepted theoretical model, we quantitatively estimate the EPC for the bond-stretching mode along the high-symmetry directions (ζ,0) and (ζ,ζ), and as a function of the azimuthal angle φ at fixed q∥. We compare our results with theoretical predictions and find that the q∥-dependence of the phonon RIXS intensity can be largely ascribed to the phonon symmetry. However, a more satisfactory prediction of the experimental results requires an accurate description of the electronic structure close to the Fermi level. Our extensive investigation indicates that Cu L3 RIXS can reliably determine the momentum dependence of EPC for the bond-stretching modes of cuprates. Moreover, the large experimental basis provided here constitutes a stringent test for advanced theoretical predictions on the EPC.
Author
Maryia Zinouyeva
Polytechnic University of Milan
R. Heid
Karlsruhe Institute of Technology (KIT)
Giacomo Merzoni
European XFEL
Polytechnic University of Milan
Riccardo Arpaia
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Universita Ca' Foscari Venezia
Nikolai Andreev
University of Rome Tor Vergata
Marco Biagi
Universita Ca' Foscari Venezia
Polytechnic University of Milan
Nicholas B. Brookes
European Synchrotron Radiation Facility (ESRF)
D. Di Castro
University of Rome Tor Vergata
Alexei Kalaboukhov
Universita Ca' Foscari Venezia
Kurt Kummer
European Synchrotron Radiation Facility (ESRF)
Floriana Lombardi
Universita Ca' Foscari Venezia
L. Martinelli
Polytechnic University of Milan
University of Zürich
Francesco Rosa
Polytechnic University of Milan
Matteo Rossi
Polytechnic University of Milan
F. Yakhou-Harris
European Synchrotron Radiation Facility (ESRF)
Lucio Braicovich
European Synchrotron Radiation Facility (ESRF)
Polytechnic University of Milan
Marco Moretti
Polytechnic University of Milan
Paolo G. Radaelli
University of Oxford
Giacomo Ghiringhelli
Polytechnic University of Milan
npj Quantum Materials
23974648 (eISSN)
Vol. 11 1 30Resonant inelastic x-ray scattering to study changes in the HTS phase diagram induced by strain and confinement
Swedish Research Council (VR) (2020-04945), 2021-01-01 -- 2024-12-31.
Subject Categories (SSIF 2025)
Atom and Molecular Physics and Optics
Condensed Matter Physics
Other Physics Topics
DOI
10.1038/s41535-026-00863-x