Mechanism of ferromagnetism in nitrogen-doped ZnO: First-principle calculations

Abstract

Based on our first-principle calculations, ZnO doped by a nonmagnetic $2p$ light element (N) is predicted to be ferromagnetic. The local magnetic moments that are mainly localized on doped N atoms introduced total moments of $1.0{\ensuremath{\mu}}_{B}/\text{atom}$. The long-range magnetic coupling of N-doped ZnO can be attributed to a $p\text{\ensuremath{-}}d$ exchange-like $p\text{\ensuremath{-}}p$ coupling interaction involving holes, which is derived from the similar symmetry and wave function between the impurity ($p$-like ${t}_{2}$) and valence $(p)$ states. We also propose a codoping mechanism, using beryllium and nitrogen as dopants in ZnO, to enhance the ferromagnetic coupling and to increase the solubility and activity.