M. Bejas
;
V. Zimmermann
;
D. Betto
;
T. D. Boyko
;
R. J. Green
;
T. Loew
;
N. B. Brookes
;
G. Cristiani
;
G. Logvenov
;
M. Minola
;
B. Keimer
;
H. Yamase
(National Institute for Materials Science)
;
A. Greco
;
M. Hepting
Collection
Citation
Description:
(abstract)The essential building blocks of cuprate superconductors are two-dimensional CuO2 sheets interspersed with charge reservoir layers. In bilayer cuprates, two closely spaced CuO2 sheets are separated by a larger distance from the subsequent pair in the next unit cell. In contrast to single-layer cuprates, prior theoretical work on bilayer systems has predicted two distinct acoustic plasmon bands for a given out-of-plane momentum transfer. Here we report random phase approximation (RPA) calculations for bilayer systems which corroborate the existence of two distinct plasmons bands. We find that the intensity of the lower-energy band is negligibly small in most parts of the Brillouin zone, whereas the higher-energy band carries significant spectral weight. We also present resonant inelastic x-ray scattering (RIXS) experiments at the O K-edge on the bilayer cuprate Y0.85Ca0.15Ba2Cu3O7 (Ca-YBCO), which show only one dispersive plasmon branch, in agreement with the RPA calculations. In addition, the RPA results indicate that the dispersion of the higher-energy plasmon band in Ca-YBCO is not strictly acoustic, but exhibits a substantial energy gap of approximately 250 meV at the two-dimensional Brillouin zone center.
Rights:
Keyword: plasmon , bilayer material, high-temperature superconductors , charge excitations
Date published: 2024-04-16
Publisher: American Physical Society (APS)
Journal:
- Physical Review B (ISSN: 1550235X) vol. 109 issue. 14 144516
Funding:
- Japan Society for the Promotion of Science JP20H01856
- Ministry of Education, Culture, Sports, Science and Technology
- Ministerio de Ciencia, Tecnología e Innovación
- Canadian Light Source
- University of Saskatchewan
- Canada Foundation for Innovation
- Natural Sciences and Engineering Research Council of Canada
- National Research Council Canada
- Canadian Institutes of Health Research
Manuscript type: Publisher's version (Version of record)
MDR DOI:
First published URL: https://doi.org/10.1103/physrevb.109.144516
Related item:
Other identifier(s):
Contact agent:
Updated at: 2024-08-30 08:30:34 +0900
Published on MDR: 2024-08-30 08:30:34 +0900
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