Ferromagnetic spin coupling of 2p impurities in band insulators stabilized by an intersite Coulomb interaction: nitrogen-doped MgO.
For a nitrogen dimer in insulating MgO, a ferromagnetic coupling between spin-polarized 2p holes is revealed by calculations based on the density functional theory amended by an on-site Coulomb interaction and corroborated by the Hubbard model. It is shown that the ferromagnetic coupling is facilitated by a T-shaped orbital arrangement of the 2p holes, which is in its turn controlled by an intersite Coulomb interaction due to the directionality of the p orbitals. We thus conjecture that this interaction is an important ingredient of ferromagnetism in band insulators with 2p dopants.
Peter Grünberg Institut, Forschungszentrum Jülich and JARA, Germany. i.slipukhina@fz-juelich.de
I
I
Slipukhina
Ph
P
Mavropoulos
S
S
Blügel
M
M
Ležaić