Spin-orbital excitations in Ca2RuO4 revealed by resonant inelastic x-ray scattering
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
The strongly correlated insulator Ca2RuO4 is considered as a paradigmatic realization of both spin-orbital physics and a band-Mott insulating phase, characterized by orbitally selective coexistence of a band and a Mott gap. We present a high resolution oxygen K-edge resonant inelastic X-ray scattering study of the antiferromagnetic Mott insulating state of Ca2RuO4. A set of low-energy (about 80 and 400 meV) and high-energy (about 1.3 and 2.2 eV) excitations are reported, which show strong incident light polarization dependence. Our results strongly support a spin-orbit coupled band-Mott scenario and explore in detail the nature of its exotic excitations. Guided by theoretical modeling, we interpret the low-energy excitations as a result of composite spin-orbital excitations. Their nature unveils the intricate interplay of crystal-field splitting and spin-orbit coupling in the band-Mott scenario. The high-energy excitations correspond to intra-atomic singlet-triplet transitions at an energy scale set by Hund's coupling. Our findings give a unifying picture of the spin and orbital excitations in the band-Mott insulator Ca2RuO4.
Date Issued
2018-03
Date Acceptance
2018-03-22
Citation
Physical Review X, 2018, 8 (1), pp.1-9
ISSN
2160-3308
Publisher
American Physical Society
Start Page
1
End Page
9
Journal / Book Title
Physical Review X
Volume
8
Issue
1
Copyright Statement
Published by the American Physical Society under the terms of
the Creative Commons Attribution 4.0 International license.
Further distribution of this work must maintain attribution to
the author(s) and the published article’s title, journal citation,
and DOI.
the Creative Commons Attribution 4.0 International license.
Further distribution of this work must maintain attribution to
the author(s) and the published article’s title, journal citation,
and DOI.
License URL
Identifier
https://journals.aps.org/prx/abstract/10.1103/PhysRevX.8.011048
Publication Status
Published
Date Publish Online
2018-03-22