No abstract

In this paper, the plane wave ultra-soft pseudopotential method was performed to analyze the effect of neutral Zn vacancy ([Formula: see text]) and O vacancy ([Formula: see text]) on the electronic and magnetic properties of Mn-doped ZnO systems. In a [Formula: see text] ZnO:Mn supercell, the sites of [Formula: see text] and [Formula: see text] were set as nearest neighbor, next nearest neighbor and far nearest neighbor relative to Mn site, respectively. The results indicated that [Formula: see text] is easier to be produced than [Formula: see text] in the ZnO:Mn system, and both kinds of defects are more likely to be generated in the nearest neighbor of Mn site. Meanwhile, the ZnO:Mn-[Formula: see text] system is p-type conductive. The farther the distance between [Formula: see text] and Mn, the better the conductivity of the system. Contrary to [Formula: see text], the ZnO:Mn-[Formula: see text] system is n-type conductive. The farther the distance between [Formula: see text] and Mn, the worse the conductivity of the system. Furthermore, the ZnO:Mn systems containing neutral [Formula: see text] or [Formula: see text] are both likely to be in antiferromagnetic phase. However, the presence of [Formula: see text] will enhance the possibility, while [Formula: see text] will weaken it.

No abstract

The electronic and magnetic properties of (Cu, N) co-doped zinc oxide (ZnO) with different Cu:N ratios of 1:2, 1:1 and 2:1 have been studied based on the density functional theory. Mono-doping of Cu or N into ZnO keeps its direct band gap semiconductor nature and exhibits its [Formula: see text]-type conduction, half-metallic properties for valance band merging below the acceptor levels in a spin direction. However, co-doping of Cu and N into ZnO greatly enhances its conductivity of the system and makes it exhibit metallic properties, the metallic properties become more obvious as the ratio of Cu:N increases from 1:2 to 2:1. Furthermore, co-doping of Cu and N into ZnO can increase magnetic moment for the interaction among Cu [Formula: see text], N [Formula: see text] and O [Formula: see text]. ZnO:2Cu–N model is the most stable model in thermodynamics but it shows anti-ferromagnetism (FM) while ZnO:Cu–N system can achieve room-temperature FM, so Cu:N ratios of 1:1 may achieve better electronic and magnetic properties by comprehensive comparison.

No abstract