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.