Volume 80, Number 3, November 2007
Article Number 37008
Number of page(s) 5
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 10 October 2007
EPL, 80 (2007) 37008
DOI: 10.1209/0295-5075/80/37008

Orbital-quenching$\hbox{--} $induced magnetism in Ba2NaOsO6

K.-W. Lee and W. E. Pickett

Department of Physics, University of California - Davis, CA 95616, USA

received 15 August 2007; accepted in final form 11 September 2007; published November 2007
published online 10 October 2007

The double perovskite Ba2NaOsO6 with heptavalent Os (d1) is observed to remain in the ideal cubic structure (i.e. without orbital ordering) despite single occupation of the t2g orbitals, even in the ferromagnetically ordered phase below 6.8 K. Analysis based on the ab initio dispersion expressed in terms of an Os t2g-based Wannier function picture, spin-orbit coupling, Hund's coupling, and strong Coulomb repulsion shows that the magnetic OsO6 cluster is near a momentless condition due to spin and orbital compensation. Quenching (hybridization) then drives the emergence of the small moment. This compensation, unprecedented in transition metals, arises in a unified picture that accounts for the observed Mott insulating behavior.

71.70.Ej - Spin-orbit coupling, Zeeman and Stark splitting, Jahn-Teller effect.
71.27.+a - Strongly correlated electron systems; heavy fermions.
77.84.Bw - Elements, oxides, nitrides, borides, carbides, chalcogenides, etc..

© Europhysics Letters Association 2007