First-principles study on the magnetic properties of transition-metal atoms doped (ZnS)12 cluster

A first-principles density functional investigation has been performed to evaluate the structural, electronic, and magnetic properties of (ZnS)(12) doped with one or two transition-metal (TM) atoms (Fe, Co, and Ni). Substitutional- and interstitial-doping are considered. The substitutional isomers are found to be most favorable for Fe-doped clusters, while the interstitial isomers are found to be most favorable for Co- and Ni-doped clusters. Magnetic coupling between the TM atoms at the nearest neighbor position is mainly governed by the competition between direct ferromagnetic and anti ferromagnetic interactions between two TM atoms via the S atom due to strong p-d hybridization. The coupling is short-ranged. Most importantly, we demonstrate that the Fe and Ni endohedral bi-doped (ZnS)(12) clusters favor the ferromagnetic state, which has potential applications in nanoscale quantum devices. (C) 2010 Elsevier B.V. All rights reserved.