First-principles studies of interlayer exchange coupling in (Ga, Cr)N-based diluted magnetic semiconductor multilayers

Abstract

Interlayer exchange coupling (IEC) in a series model diluted magnetic semiconductor multilayer consisting of two magnetic (Ga, Cr)N layers separated by non-doped or Mg-doped GaN non-magnetic spacers has been studied by first-principles calculations. The effects of the spacer thickness and hole doping to the IEC were studied systematically. For the GaN spacers without Mg doping, the IEC between two magnetic (Ga, Cr)N layers is always ferromagnetic and is clarified as an intrinsic character of the Ruderman-Kittle-Kasuya-Yoshida interaction based on a two-band model for a gapped system. For the Mg-doped GaN spacers, the IEC is antiferromagnetic, and the antiferromagnetic IEC is stable with increasing the spacer thickness.