Challenging the Prediction of Anionogenic Ferromagnetism for Rb_4O_6

摘要

For a long time, rubidium sesquioxide Rb_4O_6 has been of particular interest because its black color indicates an electronic structure that strongly differs from related systems such as regular alkali hyperoxides or peroxides. According to previous investigations, this compound exhibits a mixed valency type of behavior that is caused by differently charged dioxygen molecules, indicating that the structure may be written as Rb_4(O_2~-)_2(O_2~(2-)).The structure type Pu_2C_3 and the space group I43d, proposed by Helms and Klemm, as well as the presence of both peroxide and hyperoxide anions, have been verified by elastic and inelastic neutron scattering studies. Attema et al. performed density functional calculations within the local spin density approximation (LSDA), which suggest that Rb_4O_6 should be a half-metallic ferromagnet with the magnetic moment carried by the hyperoxide anions.