Modeling atomic force microscopy at LiNbO3 surfaces from first-principles

[Display omitted] •Atomic force microscopy images of LiNbO3 surfaces have been modeled within the density functional theory.•Different tip models have been considered ant tested.•The influence of van der Waals forces has been investigated.•The calculated AFM images are in good agreement with corresponding measurements.•The AFM contrast mechanism is found to be governed by charge accumulation at oxygen atoms. Atomic force microscopy (AFM) at LiNbO3 surfaces is simulated from first-principles. The forces acting on different atomic tip models interacting with x-cut and z-cut LiNbO3 surfaces are calculated within density functional theory. The AFM simulations are compared with atomic resolved AFM measurements. The species-dependent tip-surface interaction found in the simulation allows for the verification of microscopic models for different surfaces. In particular, it is shown that the atomic force microscopy contrast is governed by the charge accumulation at the oxygen ions. Van der Waals forces cloud the scans, without qualitatively modifying the AFM pattern. The microscopic surface models proposed here explain both the origin of the measured AFM patterns and the observed spatial resolution difference corresponding to different surface orientations.