We have studied the effect of O impurities on exchange interactions between Cr spins in (Ga,Cr)N by means of first-principles calculations based on the density functional theory. Although the magnetic moment par Cr atom is enhanced, the magnitude of ferromagnetic exchange interaction between Cr spins is reduced by co-doping with O into (Ga,Cr)N. In particular, the reduction is remarkable when the doped O atom forms a Cr-O-Cr complex. On the other hand, the ferromagnetic exchange interaction is not reduced if the O atom is separated from Cr atoms in (Ga,Cr)N. Nitrogen vacancy (Vn) also has similar effects to O impurities. The formation energy of the Cr-O-Cr complex is lower than that of Cr-VNCr, so that excessive O codoping could reduce the ferromagnetic interaction between Cr spins more seriously than the formation of N vacancies.
|Number of pages
|Physica Status Solidi (C) Current Topics in Solid State Physics
|Published - 2006
|4th International Conference on Physics and Applications of Spin-related Phenomena in Semiconductors, PASPS-IV - Sendai, Japan
Duration: 2006 Aug 15 → 2006 Aug 18