Half-metallic ferromagnetism and band gap reduction in Cu-doped zinc-blende BeO: first-principle study

In this paper, we report ferromagnetism in copper doped zinc-blende BeO. Our first-principles calculations based on spin density functional theory predicts a total magnetic moment of 1 $\mu_{\mathrm{B}}$ per copper when copper substitutes beryllium in BeO, where 0.58 $\mu_{\mathrm{B}}$ is localized at Cu atom. The results obtained show that the ferromagnetic state is 34 meV lower than the antiferromagnetic state. Calculations indicate an appreciable band gap reduction in BeO. The analysis of the partial density of states reveals that ferromagnetism and reduction of BeO band gap are principally due to the strong $p$–$d$ coupling of O and Cu.