TY - JOUR
T1 - Doping dependence of the electron-phonon coupling in two families of bilayer superconducting cuprates
AU - Peng, Yingying
AU - Martinelli, Leonardo
AU - Li, Qizhi
AU - Rossi, Matteo
AU - Mitrano, Matteo
AU - Arpaia, Riccardo
AU - Sala, Marco Moretti
AU - Gao, Qiang
AU - Guo, Xuefei
AU - De Luca, Gabriella Maria
AU - Walters, Andrew
AU - Nag, Abhishek
AU - Barbour, Andi
AU - Gu, Genda
AU - Pelliciari, Jonathan
AU - Brookes, Nicholas B.
AU - Abbamonte, Peter
AU - Salluzzo, Marco
AU - Zhou, Xingjiang
AU - Zhou, Ke Jin
AU - Bisogni, Valentina
AU - Braicovich, Lucio
AU - Johnston, Steven
AU - Ghiringhelli, Giacomo
N1 - Funding Information:
Y.Y.P. is grateful for financial support from the Ministry of Science and Technology of China (Grant No. 2019YFA0308401) and the National Natural Science Foundation of China (Grant No. 11974029). P.A. acknowledges support from the Gordon and Betty Moore Foundation, Grant No. GBMF-9452. X.J.Z. thank the financial support from the National Natural Science Foundation of China (Grant No. 11888101), the National Key Research and Development Program of China (Grant no. 2016YFA0300300) and the Strategic Priority Research Program (B) of the Chinese Academy of Sciences (Grant no. XDB25000000). S.J. is supported by the National Science Foundation under Grant No. DMR-1842056. L.M., M.M.S. and G.G. acknowledge support by the project PRIN2017 ”Quantum-2D” ID 2017Z8TS5B of the Ministry for University and Research (MIUR) of Italy. R.A. acknowledges support by the Swedish Research Council (VR) under the Project 2020-04945. This research used Diamond Light Source beam line I21 under the proposal SP20012. N.B.B. thanks Diamond Light Source for hosting him at the time the experiment was carried out at I21. This research used the beamline 2-ID of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704. The work at BNL was supported by the US Department of Energy, office of Basic Energy Sciences, Contract No. DOE-sc0012704.
Publisher Copyright:
© 2022 American Physical Society.
PY - 2022/3/15
Y1 - 2022/3/15
N2 - 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.
AB - 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.
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U2 - 10.1103/PhysRevB.105.115105
DO - 10.1103/PhysRevB.105.115105
M3 - Article
AN - SCOPUS:85126433104
SN - 2469-9950
VL - 105
JO - Physical Review B
JF - Physical Review B
IS - 11
M1 - 115105
ER -