title: Electronic entanglement in late transition metal oxides.
abstract: We present a study of the entanglement in the electronic structure of the late transition metal monoxides--MnO, FeO, CoO, and NiO--obtained by means of density-functional theory in the local density approximation combined with dynamical mean-field theory. The impurity problem is solved through exact diagonalization, which grants full access to the thermally mixed many-body ground state density operator. The quality of the electronic structure is affirmed through a direct comparison between the calculated electronic excitation spectrum and photoemission experiments. Our treatment allows for a quantitative investigation of the entanglement in the electronic structure. Two main sources of entanglement are explicitly resolved through the use of a fidelity based geometrical entanglement measure, and additional information is gained from a complementary entropic entanglement measure. We show that the interplay of crystal field effects and Coulomb interaction causes the entanglement in CoO to take a particularly intricate form.
authors.affiliation: Department of Physics and Astronomy, Uppsala University, Box 516, SE-75120 Uppsala, Sweden.
authors.forename: Patrik
authors.initials: P
authors.lastname: Thunström
authors.forename: Igor
authors.initials: I
authors.lastname: Di Marco
authors.forename: Olle
authors.initials: O
authors.lastname: Eriksson