Atomic Scale Three-Dimensional Au Nanocluster on a Rutile TiO₂ (110) Surface Resolved by Atomic Force Microscopy

The atomic structure of a three-dimensional Au nanocluster on a TiO₂ surface is important for various studies such as photocatalysis and chemical reactions on metal oxide surfaces. However, accessing the atomic structure of a metal nanocluster supported on a metal oxide surface is still challenging possibly because of its small size, complexity, and flexible structure. Here, we report a detuning imaging mode combined with an atomically sharp tip to address these challenges. Using this method, for the first time, we resolve a three-dimensional Au nanocluster on a rutile TiO₂ (110) surface. We found that the Au nanocluster was continuously adsorbed at the upper and lower terraces. Our results open up a new methodology for studying subnanometer clusters at various surfaces at an atomic scale.