Magnetic Excitations of a Half-Filled Tl-based Cuprate
Artikel i vetenskaplig tidskrift, 2026
Strong electron correlations drive Mott insulator transitions. Yet, there exists no framework to classify Mott insulators by their degree of correlation. Cuprate superconductors, with their tunable doping and rich phase diagrams, offer a unique platform to investigate the evolution of these interactions. However, spectroscopic access to a clean half-filled Mott-insulating state is lacking in compounds with the highest superconducting onset temperature. To fill this gap, we introduce a pristine, half-filled thallium-based cuprate system, Tl2Ba5Cu4Ox. Using high-resolution resonant inelastic x-ray scattering, we probe long-lived magnon excitations and uncover a pronounced kink in the magnon dispersion, marked by a simultaneous change in group velocity and lifetime broadening. Modeling the dispersion within a Hubbard-Heisenberg approach, we extract the interaction strength and compare it with other cuprate systems. Our results establish a cuprate universal relation between electron-electron interaction and magnon zone-boundary dispersion. Superconductivity seems to be optimal at intermediate correlation strength, suggesting an optimal balance between localization and itinerancy.
Författare
I. Biało
Universität Zürich
Q. Wang
Chinese University of Hong Kong
Julia Küspert
Universität Zürich
European Synchrotron Radiation Facility (ESRF)
X. Hong
Universität Zürich
Chinese University of Hong Kong
L. Martinelli
Universität Zürich
O. Gerguri
Paul Scherrer Institut
Universität Zürich
Y. Chan
Chinese University of Hong Kong
K. Von Arx
Universität Zürich
Ola Kenji Forslund
Uppsala universitet
Universität Zürich
W. R. Pudelko
Paul Scherrer Institut
Universität Zürich
C. Lin
Stanford Synchrotron Radiation Laboratory
Universität Zürich
N. C. Plumb
Paul Scherrer Institut
Yasmine Sassa
Chalmers, Fysik, Materialfysik
Kungliga Tekniska Högskolan (KTH)
Davide Betto
European Synchrotron Radiation Facility (ESRF)
Nicholas B. Brookes
European Synchrotron Radiation Facility (ESRF)
M. Rosmus
Université Paris-Saclay
Uniwersytet Jagiellonski w Krakowie
N. Olszowska
Uniwersytet Jagiellonski w Krakowie
Matthew D. Watson
Diamond Light Source
T. K. Kim
Diamond Light Source
C. Cacho
Diamond Light Source
M. Horio
University of Tokyo
M. Ishikado
Comprehensive Research Organization for Science and Society (CROSS)
H. M. Rønnow
Ecole Polytechnique Federale de Lausanne (EPFL)
J. Chang
Universität Zürich
Communications Materials
26624443 (eISSN)
Vol. 7 1 50Ämneskategorier (SSIF 2025)
Atom- och molekylfysik och optik
Den kondenserade materiens fysik
DOI
10.1038/s43246-025-01061-1