Mobile orbitons in Ca2CuO3: Crucial role of Hund's exchange
Artikel i vetenskaplig tidskrift, 2020
We investigate the CuL3 edge resonant inelastic x-ray scattering (RIXS) spectra of a quasi-1D antiferromagnet Ca2CuO3. In addition to the magnetic excitations, which are well-described by the two-spinon continuum, we observe two dispersive orbital excitations, the 3d(xy) and the 3d(yz) orbitons. We carry out a quantitative comparison of the RIXS spectra, obtained with two distinct incident polarizations, with a theoretical model. We show that any realistic spin-orbital model needs to include a finite, but realistic, Hund's exchange J(H) approximate to 0.5 eV. Its main effect is an increase in orbiton velocities, so that their theoretically calculated values match those observed experimentally. Even though Hund's exchange also mediates some interaction between spinon and orbiton, the picture of spin-orbit separation remains intact and describes orbiton motion in this compound.
Författare
R. Fumagalli
Politecnico di Milano
J. Heverhagen
Universität Stuttgart
D. Betto
Max-Planck Institute für Festkörperforschung
European Synchrotron Radiation Facility (ESRF)
Riccardo Arpaia
Politecnico di Milano
Chalmers, Mikroteknologi och nanovetenskap, Kvantkomponentfysik
M. Rossi
Stanford University
D. Di Castro
Universita degli Studi di Roma Tor Vergata
N. B. Brookes
European Synchrotron Radiation Facility (ESRF)
M. Moretti Sala
Politecnico di Milano
M. Daghofer
Universität Stuttgart
L. Braicovich
European Synchrotron Radiation Facility (ESRF)
Politecnico di Milano
K. Wohlfeld
Uniwersytet Warszawski
G. Ghiringhelli
Politecnico di Milano
Physical Review B
2469-9950 (ISSN) 2469-9969 (eISSN)
Vol. 101 20 205117Ämneskategorier
Den kondenserade materiens fysik
DOI
10.1103/PhysRevB.101.205117