A first-principles study of the magnetic properties in boron-doped ZnO

First-principles calculations based on density functional theory are performed to study the origin of ferromagnetism in boron-doped ZnO. It is found that boron atoms tend to reside at Zn sites. The induced Zn vacancy is a key factor for ferromagnetism in Zn1-xBxO (0 < x < 1) systems. The nearest oxygen atoms coordinated with the B-Zn vacancy pair show a few hole states in the 2p orbitals and induce magnetic moments. However, the configuration of two boron atoms inducing one Zn vacancy is nonmagnetic, with a lower formation energy than that of the B-Zn vacancy pair. This explains the difference between the theoretical and experimental magnetic moments.