A theoretical study of Ge adsorption on Si(0 0 1) covered with Bi nanolines

The energetic stability and the equilibrium geometry of Ge adsorption on the Si(0 0 1) surface covered with Bi nanolines were examined by ab initio total energy calculations. We find that there is an energetic preference of Ge atoms lying on the Si(0 0 1) terraces, forming Sidown-Geup mixed dimers. Further investigations reveal a repulsive interaction between the mixed dimers and the Bi nanolines, suggesting that the formation of Sidown-Geup dimers can be tailored by the presence of the Bi nanolines.