Abstract
We report on theoretical investigations of the exotic magnetism in rubidium sesquioxide , a model correlated system with an open shell. Experimental investigations indicated that is a magnetically frustrated insulator. The frustration is explained here by electronic structure calculations that incorporate the correlation between the oxygen 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 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 -electron systems.
- Received 11 June 2008
DOI:https://doi.org/10.1103/PhysRevLett.102.016401
©2009 American Physical Society