A b i n i t i o simulation of the interaction between ionic crystal surfaces and the atomic force microscope tip

Abstract

The ab initio Hartree–Fock program crystal is used to simulate the interaction of three different kinds of tips of the atomic force microscope (AFM) with the MgO(100) surface, by employing the periodic slab model. The neutral silicon atom and the SiO molecule (Si or O oriented toward the surface) are used as tip models. The relevant AFM topographical resolution and its quality are analyzed. It is shown that, depending on the chemical and electronic structure of the tip, the interpretation of the images obtained could be even opposite. The best topographic image is expected for the weak constant force (≊2×10−8 N) repulsive regime between the tip and the ionic surface. Their mutual perturbation is studied in detail.