Fractional Spin Excitations in the Infinite-Layer Cuprate CaCuO2
Journal article, 2022
We use resonant inelastic x-ray scattering (RIXS) to investigate the magnetic dynamics of the infinite-layer cuprate CaCuO2. We find that close to the (1/2,0) point, the single magnon decays into a broad continuum of excitations accounting for about 80% of the total magnetic spectral weight. Polarization-resolved RIXS spectra reveal the overwhelming dominance of the spin-flip (Delta S = 1) character of this continuum with respect to the Delta S = 0 multimagnon contributions. Moreover, its incident-energy dependence is identical to that of the magnon, supporting a common physical origin. We propose that the continuum originates from the decay of the magnon into spinon pairs, and we relate it to the exceptionally high ring exchange J(c) similar to J(1) of CaCuO2. In the infinite-layer cuprates, long-range and multisite hopping integrals are very important, and they amplify the 2D quantum magnetism effects in spite of the 3D antiferromagnetic Neel order.
Author
Leonardo Martinelli
Polytechnic University of Milan
Davide Betto
European Synchrotron Radiation Facility (ESRF)
Kurt Kummer
European Synchrotron Radiation Facility (ESRF)
Riccardo Arpaia
Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics
Lucio Braicovich
Polytechnic University of Milan
European Synchrotron Radiation Facility (ESRF)
Daniele Di Castro
University of Rome Tor Vergata
Nicholas B. Brookes
European Synchrotron Radiation Facility (ESRF)
Marco Moretti Sala
Polytechnic University of Milan
Giacomo Ghiringhelli
Polytechnic University of Milan
Physical Review X
21603308 (eISSN)
Vol. 12 2 021041Resonant 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
Atom and Molecular Physics and Optics
Other Physics Topics
Condensed Matter Physics
DOI
10.1103/PhysRevX.12.021041