Nanoscale surface patterning by adsorbate-induced faceting and selective growth:: NaCl on Cu(211)

We present a combined high-resolution electron diffraction (SPALEED) and scanning tunneling microscopy study of the insulator/metal growth system NaCl/Cu(2 1 1) which is inherently unstable against lateral pattern formation on the nanometer scale. Cu(2 1 1) is a vicinal surface with (111) terraces and intrinsic (10 0) steps (step distance 6.25 Angstrom). This starting surface restructures upon NaCl deposition when the growth temperature exceeds similar to270 K. The initially flat surface is transformed into a periodic one-dimensional hill-and-valley structure consisting of (3 11) and (111) facets. NaCl grows selectively on (3 11) facets only, thereby creating a regular surface pattern with alternating stripes of bare Cu and chemically inert NaCl-covered areas. The lateral stripe spacing can be varied from similar to30 A at 300 K to similar to230 A at 600 K via the growth/annealing temperature. The present restructuring process is governed by the interplay between energetics and kinetics, namely by (1) the tendency to form (100)-terminated NaCl layers, (2) energetically favored interfacial matching between NaCl(1 0 0) and Cu(311), and (3) sufficient mobility of the substrate surface to allow for Cu mass transport. (C) 2001 Elsevier Science B.V. All rights reserved.