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Islands and holes as measures of mass balance in growth of the (root 3x root 3)R30 degrees phase of Ag on Si(111)

TitleIslands and holes as measures of mass balance in growth of the (root 3x root 3)R30 degrees phase of Ag on Si(111)
Publication TypeJournal Article
Year of Publication2010
AuthorsBelianinov A, Unal B, Lu N, Ji M, Ho KM, Wang CZ, Tringides MC, Thiel PA
Journal TitlePhysical Review B
Volume82
Pages245413
Date Published12
Type of ArticleArticle
ISBN Number1098-0121
Accession NumberISI:000286896000002
Keywords2-dimensional adatom gas, ag/si(111), au, deposition, electrical-conduction, model, reconstructions, restructuring process, scanning-tunneling-microscopy, surface
Abstract

It is well known that conversion of Si(111)-(7x7) into the (root 3x root 3)R30 degrees phase of adsorbed Ag requires a change in the Si density, and causes formation of islands and holes at the surface. By mass balance, the ratio of areas of islands and holes (R-IH) should be approximately 1. However, we find that the ratio is significantly higher, depending on preparation conditions. A possible explanation would be that there are different types of (root 3x root 3)R30 degrees structures. However, neither scanning tunneling microscopy nor density-functional theory (implemented as a genetic algorithm search) supports this explanation. We propose that the edges of the islands contain excess Ag which becomes available to expand the holes, when the island perimeter decreases. Under certain conditions, excess Ag is also made available by dissolution of small islands that are Ag rich.
URL<Go to ISI>://000286896000002
DOI10.1103/PhysRevB.82.245413
Alternate JournalPhys. Rev. B