Apr 29, 2021
Research: Unraveling the Orbital Physics in a Canonical Orbital System KCuF3
Angular dependence of orbital excitations σ-(purple) and π polarized (green) incident x-rays. The vertical dashed lines depict the averaged peak values of fitted dd excitations. (b) Calculated angular-dependent spectra. The vertical dashed lines show the calculated values of dd excitations.
Periodic orderings of charge, spin, and orbital degrees of freedom are characteristics of transition metal oxides. These ordered but symmetry-broken states are often in connection with physical properties such as the high-temperature superconductivity and the colossal magnetoresistance. Similar to the collective spin wave in antiferromagnetically-ordered Heisenberg systems, the hallmark of the orbital ordering is the collective orbital wave, orbiton. Despite the reports in quasi-one-dimensional cuprates, studies of orbiton in real orbital ordering systems have been lacking. We report the study of spin and orbital excitations in a canonical orbital order system KCuF3 using the momentum-dependent resonant inelastic X-ray scattering (RIXS), establishing a new avenue for the study of orbital physics.
J. Li, L. Xu, M. Garcia-Fernandez, A. Nag, H. C. Robarts, A. C. Walters, X. Liu, J. Zhou, K. Wohlfeld, J. van den Brink, H. Ding, K.-J. Zhou
Unraveling the Orbital Physics in a Canonical Orbital System KCuF3,
Phys. Rev. Lett. 126, 106401(2021) (arXiv)