title: The computational materials design of (Ga, Cr)N: effects of co-doping on exchange interactions.
abstract: We investigate the effect of O or Be co-doping on the exchange interaction between Cr spins in (Ga, Cr)N by means of first-principles calculations based on the density-functional theory. The ferromagnetic exchange interactions are reduced by doping Be around Cr. On the other hand, O doping reduces the ferromagnetic interaction remarkably only for the case of Cr-O-Cr complex formation. The enhancement of the ferromagnetic exchange interaction cannot be achieved by doping O or Be impurities. However, the O and Be impurities can help the clustering of Cr atoms due to the enhancement of the attractive interaction between Cr atoms.
authors.affiliation: Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Nakano
authors.forename: Masafumi
authors.initials: M
authors.lastname: Shirai
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Miura
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Nagao