Effect of fixed particles on periodic adatom arrangements on Si 111/unreconstructed surfaces

Time-independent and -dependent Monte Carlo simulations of a two-dimensional lattice gas were performed to investigate the effect of fixed particles on periodic adatom arrangements on Si 111.1=1 surfaces. In both the simulations introducing fixed particles, domains of the periodic structures were divided into small fragments around them. This can be explained by the fixed particles reducing the degree of freedom of the adatom configurations so the number of ways of reaching the uniform configuration is highly restricted. Based on the simulations, we predict that a large 1=1 region without any obstacle impurities is desirable to obtain a large periodic structure of Si adatoms. q1998 Elsevier Science B.V. All rights reserved