<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Slipukhina, I.</style></author><author><style face="normal" font="default" size="100%">Mavropoulos, Ph.</style></author><author><style face="normal" font="default" size="100%">S. Blügel</style></author><author><style face="normal" font="default" size="100%">Lezaic, M.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Ferromagnetic Spin Coupling of 2p Impurities in Band Insulators Stabilized by an Intersite Coulomb Interaction: Nitrogen-Doped MgO</style></title><secondary-title><style face="normal" font="default" size="100%">PHYSICAL REVIEW LETTERS</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2011</style></year><pub-dates><date><style  face="normal" font="default" size="100%">SEP 21</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">13</style></number><volume><style face="normal" font="default" size="100%">107</style></volume><pages><style face="normal" font="default" size="100%">137203</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">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.</style></abstract></record></records></xml>