Photoelectronic scoping of adatoms, atomic vacancies, and the outermost layer of a surface

TL;DR

This paper introduces a straightforward photoelectronic method to analyze atomic-scale surface features, revealing bond strength, electron polarization, and core band effects at defect sites on various surfaces.

Contribution

It presents a novel, simple technique for atomistic, local, and quantitative surface analysis that complements existing microscopy and spectroscopy methods.

Findings

Undercoordinated atoms form shorter, stronger bonds

Defects and adatoms cause electron polarization and screening effects

Core band splitting observed at defect sites

Abstract

An effective yet simple means disclosed herewith has allowed us to gain the atomistic, local, and quantitative information of bonds and electrons at sites surrounding undercoordinated atoms, complementing the scanning tunneling microscopy/spectroscopy and photoelectron spectroscopy (XPS). Examining Rh and Pt surfaces with and without adatoms and graphite surface with and without atomic vacancies, we confirmed that: i) bonds between undercoordinated atoms become shorter and stronger; ii) subjective polarization happens to the valence electrons of defects or adatoms by the densely entrapped bonding electrons, which in turn screens and splits the crystal field and hence the core band of the specimen.