Ab initio Calculation of The Magnetic Properties of Oxygen Impurity Complexes in CdSe

[摘要] We have investigated the magnetic dipole moments of interstitial oxygen molecules (O2) and their interactions in CdSe by using spin-dependent first-principle calculations based on the local density functional (DFT) theory. We constructed supercells of Cd64Se64by repeating the primitive cell Cd2Se24×4×2 times. Then an O2molecule aligned along c-axis was added to the center of the CdSe cage. The charge densities of the complexes were then computed for both spin-up and spin-down electrons. Their difference indicates that O2molecule in CdSe is paramagnetic, although its magnetic dipole moment is lower than that in free space. Two such O2molecules were then placed either (a) parallel to each other in side-by-side supercells or (b) in neighboring supercells on top of each other. The computed energies of the resultant magnetic structures suggest that the two O2magnetic moments interact anti-ferromagnetically in case (a) but do not interact in (b).

[发布机构] Key Laboratory of Beam Technology and Material Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing; 100875, China^1;Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun; 130023, China^2;Physics Department, University of California and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley; CA; 94720, United States^3

[关键词] Ab initio calculations;First principle calculations;Free spaces;Interstitial oxygen;Local density functional;Oxygen impurity;Side by sides;Spin-down electrons