Potential-dependent reconstruction at ordered Au(100)-aqueous interfaces as probed by atomic-resolution scanning tunneling microscopy

Detailed atomic-resolution images of ordered Au(100) surfaces in aqueous 0.1M HClO₄ as obtained by in situ scanning tunneling microscopy (STM) are reported as a function of electrode potential. Below about -0.25 V (versus saturated calomel electrode), the (1×{}1) surface reconstructs to form corrugated quasihexagonal domains. Multiple distinct, yet related, structures are formed that resemble those postulated from diffraction measurements. The reconstruction can be lifted by returning to 0.2 V. The results demonstrate the promise of atomic-resolution STM for examining reconstruction at ordered electrochemical surfaces.