Ab initio characterization of transition-metal-doped Si nanocrystals

We investigate the influence of transition-metal doping on silicon nanocrystals by means of first-principles calculations within a supercell approach. We focus on the energetic stability of different doping sites and on electronic and magnetic properties of the most stable configurations. Remarkable differences concerning the magnetic moments and the electronic properties are found between iron and manganese and for inclusion of strong electron correlation. In addition, a self-purification effect, which hampers an incorporation of transitionmetal atoms in small nanocrystals, is observed.