Doping dependence of the electron-phonon coupling in two families of bilayer superconducting cuprates
Journal article, 2022
While electron-phonon coupling (EPC) is crucial for Cooper pairing in conventional superconductors, its role in high-Tc superconducting cuprates is debated. Using resonant inelastic x-ray scattering at the oxygen K edge, we study the EPC in Bi2Sr2CaCu2O8+δ (Bi2212) and Nd1+xBa2-xCu3O7-δ (NBCO) at different doping levels ranging from heavily underdoped (p=0.07) to overdoped (p=0.21). We analyze the data with a localized Lang-Firsov model that allows for the coherent excitations of two phonon modes. While electronic band dispersion effects are non-negligible, we are able to perform a study of the relative values of EPC matrix elements in these cuprate families. In the case of NBCO, the choice of the excitation energy allows us to disentangle modes related to the CuO chains and the CuO2 planes. Combining the results from the two families, we find the EPC strength decreases with doping at q∥=(-0.25,0) r.l.u., but has a nonmonotonic trend as a function of doping at smaller momenta. This behavior is attributed to the screening effect of charge carriers. We also find that the phonon intensity is enhanced in the vicinity of the charge-density-wave excitations while the extracted EPC strength appears to be less sensitive to their proximity. By performing a comparative study of two cuprate families, we are able to identify general trends in the EPC for the cuprates and provide experimental input to theories invoking a synergistic role for this interaction in d-wave pairing.
Author
Y. Y. Peng
Beijing University of Technology
Leonardo Martinelli
Polytechnic University of Milan
Qizhi Li
Beijing University of Technology
Matteo Rossi
Polytechnic University of Milan
Matteo Mitrano
University of Illinois
Riccardo Arpaia
Polytechnic University of Milan
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Marco Moretti Sala
Polytechnic University of Milan
Qiang Gao
Chinese Academy of Sciences
Xuefei Guo
University of Illinois
Gabriella M. De Luca
University of Naples Federico II
CNR - SuPerconducting and other INnovative materials and devices institute, Napoli
Andrew C. Walters
Diamond Light Source
Abhishek Nag
Diamond Light Source
Andi Barbour
Brookhaven National Laboratory
Genda Gu
Brookhaven National Laboratory
Jonathan Pelliciari
Brookhaven National Laboratory
Nicholas B. Brookes
European Synchrotron Radiation Facility (ESRF)
Peter Abbamonte
University of Illinois
Marco Salluzzo
CNR - SuPerconducting and other INnovative materials and devices institute, Napoli
Xingjiang Zhou
Chinese Academy of Sciences
Ke Jin Zhou
Diamond Light Source
Valentina Bisogni
Brookhaven National Laboratory
Lucio Braicovich
Polytechnic University of Milan
European Synchrotron Radiation Facility (ESRF)
Steven Johnston
University of Tennessee
Giacomo Ghiringhelli
Polytechnic University of Milan
Physical Review B
2469-9950 (ISSN) 2469-9969 (eISSN)
Vol. 105 11 115105Subject Categories
Atom and Molecular Physics and Optics
Other Physics Topics
Condensed Matter Physics
DOI
10.1103/PhysRevB.105.115105