title: Crystal-field splitting and correlation effect on the electronic structure of A2IrO3.
abstract: The electronic structure of the honeycomb lattice iridates Na(2)IrO(3) and Li(2)IrO(3) has been investigated using resonant inelastic x-ray scattering (RIXS). Crystal-field-split d-d excitations are resolved in the high-resolution RIXS spectra. In particular, the splitting due to noncubic crystal fields, derived from the splitting of j(eff)=3/2 states, is much smaller than the typical spin-orbit energy scale in iridates, validating the applicability of j(eff) physics in A(2)IrO(3). We also find excitonic enhancement of the particle-hole excitation gap around 0.4 eV, indicating that the nearest-neighbor Coulomb interaction could be large. These findings suggest that both Na(2)IrO(3) and Li(2)IrO(3) can be described as spin-orbit Mott insulators, similar to the square lattice iridate Sr(2)IrO(4).
authors.affiliation: Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada.
authors.forename: H
authors.initials: H
authors.lastname: Gretarsson
authors.affiliation: Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada.
authors.forename: J P
authors.initials: JP
authors.lastname: Clancy
authors.affiliation: CMP&MS Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: X
authors.initials: X
authors.lastname: Liu
authors.affiliation: CMP&MS Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: J P
authors.initials: JP
authors.lastname: Hill
authors.affiliation: CMP&MS Department, Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.forename: Emil
authors.initials: E
authors.lastname: Bozin
authors.affiliation: Indian Institute of Science Education and Research Mohali, Sector 81, SAS Nagar, Manauli PO 140 306, Punjab, India.
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Singh
authors.affiliation: I. Physikalisches Institut, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Manni
authors.affiliation: I. Physikalisches Institut, Georg-August-Universität Göttingen, D-37077 Göttingen, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Gegenwart
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: Jungho
authors.initials: J
authors.lastname: Kim
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: A H
authors.initials: AH
authors.lastname: Said
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: D
authors.initials: D
authors.lastname: Casa
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: T
authors.initials: T
authors.lastname: Gog
authors.affiliation: Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, USA.
authors.forename: M H
authors.initials: MH
authors.lastname: Upton
authors.affiliation: Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea.
authors.forename: Heung-Sik
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea.
authors.forename: J
authors.initials: J
authors.lastname: Yu
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors.forename: Vamshi M
authors.initials: VM
authors.lastname: Katukuri
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Hozoi
authors.affiliation: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
authors.forename: Jeroen
authors.initials: J
authors.lastname: van den Brink
authors.affiliation: Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada.
authors.forename: Young-June
authors.initials: YJ
authors.lastname: Kim