Role of nitrogen split interstitial defects in the magnetic properties of Cu-doped GaN

Abstract

Abstract:Cu-doped GaN thin films are grown by plasma-assisted molecular beam epitaxy. With nitrogen plasma only, films phase segregate into GaN and Cu-rich alloys. In contrast, when nitrogen-hydrogen plasma is used, the films are single-phased Ga 1-x Cu x N, with x as high as 0.04.Contrary to earlier studies, however, these films are not ferromagnetic, but rather paramagnetic in nature. First-principles calculations indicate that although each substitutional Cu Ga exhibits a moment of 1 μ B /Cu, it can be suppressed by neighboring intrinsic defects such as N splitinterstitials. PACS: 75.50.Pp, 71.15.Mb, 81.15.Hi,61.72.jj, 64.75.Qr *lianli@uwm.edu 2