New insights into the structure of the Ag(111)-p(4 × 4)-O phase: high-resolution STM and DFT study.

Abstract

The atomic structure of the Ag(111)-p(4 × 4)-O phase was reexamined with scanning tunneling microscopy (STM) and density functional theory. We discovered two different phases with the same (4 × 4) periodicity and demonstrated that the accepted Ag6 model is incompatible with high-resolution oxygen-sensitive STM images. Using bias dependencies of the STM images, we have shown that the p(4 × 4) phase is highly nonuniform, with local oxygen coverage varying from 1/8 ML up to 1/2 ML.