title: Spin-orbital entanglement and violation of the Goodenough-Kanamori rules.
abstract: We point out that large composite spin-orbital fluctuations in Mott insulators with t(2g) orbital degeneracy are a manifestation of quantum entanglement of spin and orbital variables. This results in a dynamical nature of the spin superexchange interactions, which fluctuate over positive and negative values, and leads to an apparent violation of the Goodenough-Kanamori rules.
authors.affiliation: Max-Planck-Institut für Festkörperforschung, Heisenbergstrasse 1, D-70569 Stuttgart, Germany.
authors.forename: Andrzej M
authors.initials: AM
authors.lastname: Oleś
authors.forename: Peter
authors.initials: P
authors.lastname: Horsch
authors.forename: Louis Felix
authors.initials: LF
authors.lastname: Feiner
authors.forename: Giniyat
authors.initials: G
authors.lastname: Khaliullin