Abstract
Mixed-valent RbO provides an exceptional prototype material for studying the interplay between local correlations (Hubbard ) and electron kinetic energy () in the open -electron shell. Based on a first-principles calculation we show that depending on ratio, when tuned by external pressure, RbO exhibits a surprising sequence of phase transitions between strongly correlated antiferromagnetic insulator, ferromagnetic insulator (), moderately correlated ferromagnetic half-metal (), and finally itinerant nonmagnetic metal (). This sequence, which is counterintuitive to the usual Bethe-Slater scenario, in addition exhibits the fully spin-polarized half-metallic ferromagnetic state revealed within the insulator-metal transition regime.
- Received 10 February 2012
DOI:https://doi.org/10.1103/PhysRevB.85.205125
©2012 American Physical Society