Reconstruction induced faceting

To proceed, we must describe the effective driving force and the effective interactions between steps on this mesoscopic scale. We focus here on two cases of recent experimental and theoretical interest current-induced step bunching on Si( 111) surfaces - " and reconstruction-induced faceting as seen a number of systems including the O/Ag(110) and Si(lll) surfaces" In both cases interesting 2D step patterns can arise from the competition between a driving force that promotes step bunching, and the effects of step repulsions, which tend to keep steps uniformly spaced. 

The (111) surface of TMCs is a polar surface, and the surface atom loses three coordinated atoms in the vacuum side. As mentioned in Sec. I, all the TMC(lll) surfaces [except for VC(lll)] are covered with metal layers. The polar surface is usually unstable because of its large electrostatic potential at the surface, which usually induces surface reconstructions or facetings. However, no reconstruction of TMC( 111) has been found except for the VC( 111) surface (8,9), suggesting... 

From the microscopic point of view, again the CO-induced 1 x 2- 1 x 1 structural transformation of the Pt(l 10) surface (as also underlying the mechanism of temporal oscillations) is of crucial importance for the development of facets, as becomes evident from the fact that this effect is restricted to conditions of high stationary CO coverages. Simply speaking, CO adsorption lifts the 1 x 2 reconstruction and simultaneously creates... 

Annealing in UHV, which is one of the general methods of obtaining clean and well-defined surfaces, could not produce the expected clean GaN surfaces only postannealing below 550°C could reduce (but not eliminate) surface contamination while maintaining the stoichiometry however, it did not induce any surface reconstructions. The annealing treatment at high temperature removed surface contamination completely, but facets started to appear on the GaN surface above 550° C and the surface become Ga-rich with unbalanced stoichiometry (Table 1). 

At o < 0.5 ML, the adsorbate starts to induce a (1 x 2) MR reconstruction of the surface. Oxygen atoms occupy every other fcc(lll) facet site along both sides of a metal row in the close-packed direction. Each adsorbate interacts with two atoms at the surface and one atom in the second substrate layer. 

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