title: Challenge of magnetism in strongly correlated open-shell 2p systems.
abstract: We report on theoretical investigations of the exotic magnetism in rubidium sesquioxide Rb4O6, a model correlated system with an open 2p shell. Experimental investigations indicated that Rb4O6 is a magnetically frustrated insulator. The frustration is explained here by electronic structure calculations that incorporate the correlation between the oxygen 2p electrons and deal with the mixed-valent oxygen. This leads to a physical picture where the symmetry is reduced because one third of the oxygen in Rb4O6 is nonmagnetic while the remaining two thirds assemble in antiferromagnetic arrangements. A degenerate, insulating ground state with a large number of frustrated noncollinear magnetic configurations is confidently deduced from the theoretical point of view. These findings demonstrate in general the importance of electron-electron correlations in open-shell p-electron systems.
authors.affiliation: Institut für Anorganische und Analytische Chemie, Johannes Gutenberg-Universität, D-55099 Mainz, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Winterlik
authors.forename: Gerhard H
authors.initials: GH
authors.lastname: Fecher
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Jenkins
authors.forename: Claudia
authors.initials: C
authors.lastname: Felser
authors.forename: Claus
authors.initials: C
authors.lastname: Mühle
authors.forename: Klaus
authors.initials: K
authors.lastname: Doll
authors.forename: Martin
authors.initials: M
authors.lastname: Jansen
authors.forename: Leonid M
authors.initials: LM
authors.lastname: Sandratskii
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kübler