Regional chemical potential analysis for material surfaces

TL;DR

This paper introduces a local regional chemical potential analysis method to quantify atomic and molecular surface interactions, aiding in interpreting AFM images through covalent bonding insights.

Contribution

It presents a novel RCP analysis approach based on an energy window scheme, linking chemical bonding forces with local chemical potential in surface systems.

Findings

RCP visualizes electron-donating regions on surfaces.

RCP correlates with chemical bonding forces in AFM.

Method effectively analyzes high-resolution AFM images.

Abstract

We propose a local regional chemical potential (RCP) analysis method based on an energy window scheme to quantitatively estimate the selectivity of atomic and molecular adsorption on surfaces, as well as the strength of chemical bonding forces between a probe tip and a surface in atomic force microscopy (AFM) measurements. In particular, focusing on the local picture of covalent bonding, we use a simple H$_2$ molecular model to demonstrate a clear relationship between chemical bonding forces and the local RCP. Moreover, density functional theory calculations on molecular systems and diamond C(001) surfaces reveal that the local RCP at the surfaces successfully visualizes electron-donating regions such as dangling bonds and double bonds. These results suggest that the local RCP can serve as an effective measure to analyze high-resolution non-contact or near-contact AFM images enhanced by chemical bonding forces.