title: Spin-orbit coupling in the Mott insulator Ca(2)RuO(4).
abstract: O 1s x-ray absorption study of the Mott insulator Ca(2)RuO(4) shows that the orbital population of the 4d t(2g) band dramatically changes with temperature. In addition, spin-resolved circularly polarized photoemission study of Ca(2)RuO(4) shows that a substantial orbital angular momentum is induced in the Ru 4d t(2g) band. Based on the experimental results and model Hartree-Fock calculations, we argue that the cooperation between the strong spin-orbit coupling in the Ru 4d t(2g) band and the small distortion of the RuO(6) octahedra causes the interesting changeover of the spin and orbital anisotropy as a function of temperature.
authors.affiliation: Department of Complexity Science and Engineering, University of Tokyo, Tokyo 113-0033, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Mizokawa
authors.forename: L H
authors.initials: LH
authors.lastname: Tjeng
authors.forename: G A
authors.initials: GA
authors.lastname: Sawatzky
authors.forename: G
authors.initials: G
authors.lastname: Ghiringhelli
authors.forename: O
authors.initials: O
authors.lastname: Tjernberg
authors.forename: N B
authors.initials: NB
authors.lastname: Brookes
authors.forename: H
authors.initials: H
authors.lastname: Fukazawa
authors.forename: S
authors.initials: S
authors.lastname: Nakatsuji
authors.forename: Y
authors.initials: Y
authors.lastname: Maeno