Collective Nature of Orbital Excitations in Layered Cuprates in the Absence of Apical Oxygens
Journal article, 2024
We have investigated the 3d orbital excitations in CaCuO2 (CCO), Nd2CuO4 (NCO), and La2CuO4 (LCO) using high-resolution resonant inelastic x-ray scattering. In LCO they behave as well-localized excitations, similarly to several other cuprates. On the contrary, in CCO and NCO the dxy orbital clearly disperses, pointing to a collective character of this excitation (orbiton) in compounds without apical oxygen. We ascribe the origin of the dispersion as stemming from a substantial next-nearest-neighbor (NNN) orbital superexchange. Such an exchange leads to the liberation of the orbiton from its coupling to magnons, which is associated with the orbiton hopping between nearest neighbor copper sites. Finally, we show that the exceptionally large NNN orbital superexchange can be traced back to the absence of apical oxygens suppressing the charge transfer energy.
Author
L. Martinelli
Polytechnic University of Milan
University of Zürich
K. Wohlfeld
University of Warsaw
Jonathan Pelliciari
Brookhaven National Laboratory
Massachusetts Institute of Technology (MIT)
Riccardo Arpaia
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Nicholas B. Brookes
European Synchrotron Radiation Facility (ESRF)
D. Di Castro
University of Rome Tor Vergata
Mirian G. Fernandez
Diamond Light Source
Mingu Kang
Massachusetts Institute of Technology (MIT)
Yoshiharu Krockenberger
NTT Basic Research Laboratories
Kurt Kummer
European Synchrotron Radiation Facility (ESRF)
Daniel E. McNally
Paul Scherrer Institut
Eugenio Paris
Paul Scherrer Institut
T. Schmitt
Paul Scherrer Institut
Hideki Yamamoto
NTT Basic Research Laboratories
Andrew C. Walters
Diamond Light Source
Ke Jin Zhou
Diamond Light Source
Lucio Braicovich
European Synchrotron Radiation Facility (ESRF)
Polytechnic University of Milan
Riccardo Comin
Massachusetts Institute of Technology (MIT)
Marco Moretti Sala
Polytechnic University of Milan
Thomas P. Devereaux
Stanford Engineering
Stanford University
M. Daghofer
University of Stuttgart
Giacomo Ghiringhelli
Polytechnic University of Milan
Physical Review Letters
0031-9007 (ISSN) 1079-7114 (eISSN)
Vol. 132 6 066004Resonant 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
Condensed Matter Physics
DOI
10.1103/PhysRevLett.132.066004
PubMed
38394564