Electronic and magnetic properties of Co-doped ZnO: First principles study

In order to investigate the electronic and magnetic properties of Co-ZnO alloys, we used a full potential linearized augmented plane wave (FPLAPW) method within the density functional theory (DFT), as implement in the WIEN2K package. This work is carried out within the LSDA approximation as the exchange-correlation potential. We have modeled ZnO doped with 6.25, 12.5, and 18.75% of Co. It pointed out that the band gap decrease and the magnetic moments increase with the atomic fraction of Cobalt. The ZnxCo1-xO is found to be a semiconductor, where the filled-states are located in the valence bands and the empty ones above the conduction band edge. The filled and empty d-states are also shown to shift downwards and upwards in the valence and the conduction bands, respectively, with increase in the U potential. The analysis of the partial density of states reveals that the reduction of the ZnO band gap is due principally to the strong p-d interaction of O and Co. (c) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim