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approvedpatterson_extended_abstract-2.pdf2015-06-19 08:14:31Charles Patterson

Abstracts

Author: Charles H. Patterson
Requested Type: Oral
Submitted: 2015-03-13 07:33:26

Co-authors: S. Banerjee

Contact Info:
Trinity College Dublin
na
Dublin 2,   12345
Ireland

Abstract Text:
Au adsorbed on the Si(111) surface leads to a complex set of surface structures as a function of coverage and preparation conditions. Observed features include the (5x2), (R3xR3)R30 and (6x6) reconstructions as well as more complex reconstructions and dense networks of domain walls. Here we report calculations of atomic and electronic structures, optical spectra and STM images for these reconstructions and domain wall networks and account for the variety of structures observed in terms of an instability of the Fermi surface of the conjugate honeycomb chain trimer (CHCT) structure. Structures in which top-layer Si atoms have four or even five Au neighbors are stable. Five coordinate Si atoms with four Au neighbors in a butterfly wing shape are a common feature of models for the (5x2) reconstruction as well as domain walls in which Au triangles over H3 sites are inserted between T4-site domains. The large Fermi surface of the CHCT structure results in instability in the CHCT structure which is relieved by addition of further Au atoms or adatoms which act as electron donors.

Comments:
In (R3xR3)R30o R is sqrt and o should be superscripted

Category of abstract is partly 2.0 partly surface electronic structure (unlisted)