First-principles study of the stability of atomic Ag lines epitaxial to self-assembled Bi nanolines

The stability of single-atom-wide Ag lines epitaxial to a Bi nanoline (a double line of Bi dimers self-assembled on the Si(001) surface) is examined from first principles. The lattice-matched Ag line, which has a coincident-site lattice (CSL) relationship with the Bi nanoline, is found more stable than pseudomorphic ones such as monomer and dimer lines. The greater stability of the single-row CSL line against the double-row one indicates the feasibility of single-row lines. The greater stability of the triple-row line however suggests that the single-row lines should be grown under kinetically controlled conditions.