In air STM observation of Au(111) surface disturbance including Au magic fingers as modified by solvent choice

Abstract

A widely studied surface phenomena on Au(111) is the formation of Au magic fingers, which were first discovered nearly 20 years ago. A variety of experimental conditions have been used to observe the formation of Au magic fingers with a slight preference to ultra-high vacuum and low temperature studies. With the advances in scanning probe techniques, it is possible to study these unique structures under more relevant conditions including in air and at room temperature. After exposure to a 0.1 M solvent solution, Au(111) displayed three types of surface disturbances, including the formation of Au magic fingers, based on the identity of the solvent. The type of disturbance was dependent on the solvent molecule's characteristics, specifically its total charge and its electrolytic behavior in aqueous environments. The mechanism of disturbance relied on a strong tip-surface interaction and the mass transport of Au atoms, which was modified by the solvent selected. Overall, the ability to form organized nanostructures, like Au magic fingers, in a repeated way in environments outside of UHV and without a protective liquid layer increases the utility of these structures into a wider array of fields and applied areas.