In situ Video-STM study of the potential-induced (1 x 1) → hex transition on Au(100) electrode surfaces in Cl- containing solution

The potential-induced (1 x 1) --> hex transition on Au(100) electrodes in 0.01 M Na2SO4 + 1 mM HCl was studied by in situ scanning tunneling microscopy at high time resolution (Video-STM). According to these observations the elementary units of the hex surface reconstruction, hexagonally-ordered strings in the Au surface layer, are highly dynamic nanoscale objects. Isolated hex strings exhibit dynamic fluctuations in structure and position on the millisecond timescale. These fluctuations exceed the mobility of multistring hex domains by several orders of magnitude and can be explained by collective dynamic processes within the strings. Furthermore, the observations reveal a novel ID mass transport mechanism along the strings, details on the nucleation and growth of hex strings and complex string restructuring processes, facilitating hex domain ripening. (C) 2004 Elsevier B.V. All rights reserved.