Standardization of Chemically Selective Atomic Force Microscopy for Metal Oxide Surfaces
Philipp Wiesener, Stephan Förster, Milena Merkel, Bertram Schulze Lammers, Harald Fuchs, Saeed Amirjalayer, Harry Mönig
Abstract
The structures of metal oxide surfaces and inherent defects are vital for a variety of applications in materials science and chemistry. While scanning probe microscopy can reveal atomic-scale details, elemental discrimination usually requires indirect assumptions and extensive theoretical modeling. Here, atomic force microscopy with O-terminated copper tips on a variety of sample systems demonstrates not only a clear and universal chemical contrast but also immediate access to the atomic configuration of defects. The chemically selective contrast is explained by purely electrostatic interactions between the negatively charged tip-apex and the strongly varying electrostatic potential of metal and oxygen sites. These results offer a standardized methodology for the direct characterization of even the most complex metal oxide surfaces, providing fundamental insight into atomic-scale processes in these material systems.