Reconstruction-dependent orientation of Ag(111) films on Si(001).

The growth of Ag on 4\ifmmode^\circ\else\textdegree\fi{}-misoriented, single-domain Si(001) surfaces at 130 K yields continuous and epitaxial overlayers with a (111) orientation. The close-packed rows of Ag atoms are parallel to the (2\ifmmode\times\else\texttimes\fi{}1) dimer rows and run perpendicular to the step edges. The dimer orientation can be rotated by 90\ifmmode^\circ\else\textdegree\fi{} by inducing a (3\ifmmode\times\else\texttimes\fi{}2) reconstruction on the Si(001) surface. Again, single-crystal Ag(111) films are obtained; however, their in-plane orientation is now rotated by 90\ifmmode^\circ\else\textdegree\fi{}. In this case, the close-packed rows of Ag atoms are aligned parallel to the step edges.