Temperature-dependent growth and orientation selection of ice on Au(111)

Abstract

Although the structures of solid water on surfaces have been extensively studied, the role of deposition temperature in determining growth morphology and in-plane orientation remains unclear. In this study, we examine ice growth on Au(111) as a function of deposition temperature using low-energy electron diffraction (LEED) and atomic force microscopy. The characteristic 3×3R30° periodicity of bilayer hexagonal ice (BHI) observed near 136 K disappears above ∼144 K. This indicates that BHI is a kinetically stabilized phase that is only accessible under low-temperature deposition conditions. At elevated deposition temperatures, as exemplified by deposition at 148 K, multilayer ice Ih forms three rotational domains, resulting in an eighteen-spot LEED pattern. In contrast, in our amorphous solid water annealing experiments, crystallization produced a six-spot pattern rather than the eighteen-spot pattern. This indicates that the resulting structure is determined by the deposition temperature rather than simply by post-growth thermal equilibration. However, a simple lattice-overlap model based solely on geometric commensurability under the assumption of an ice basal plane fails to reproduce the experimentally observed rotational domains. These findings suggest that local interfacial environments on Au(111), including step-edge regions, may influence the macroscopic in-plane orientation of ice.