2015/01/26 by Gábor Mándi, Gilberto Teobaldi, Krisztián Palotás · 1 citation
Biochemistry, Genetics and Molecular Biology · Physics and Astronomy · #Advanced Electron Microscopy Techniques and Applications #Apex (geometry) #Atomic units #Force Microscopy Techniques and Applications #Highly oriented pyrolytic graphite #Orientation (vector space) #Quantum tunnelling #Scanning tunneling microscope #Surface (topology) #Surface and Thin Film Phenomena #Tungsten #cond-mat.mes-hall #cond-mat.mtrl-sci #physics.chem-ph #physics.comp-ph
paper · pdf · doi:10.1016/j.progsurf.2015.02.001
published as Progress in Surface Science 90, 223-238 (2015) · Progress in Surface Science, accepted for publication, 25 pages manuscript, 9 figures, abstract shortened
arxiv created 2015/01/26 · openalex publication_date 2015/03/06 · arxiv updated 2015/03/17 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We introduce a statistical correlation analysis method to obtain information on the local geometry and orientation of the tip used in scanning tunneling microscopy (STM) experiments based on large scale simulations. The key quantity is the relative brightness correlation of constant-current topographs between experimental and simulated data. This correlation can be analyzed statistically for a large number of modeled tip orientations and geometries. Assuming a stable tip during the STM scans and based on the correlation distribution, it is possible to determine the tip orientations that are most likely present in an STM experiment, and exclude other orientations. This is especially important for substrates such as highly oriented pyrolytic graphite (HOPG) since its STM contrast is strongly tip dependent, which makes interpretation and comparison of STM images very challenging. We illustrate the applicability of our method considering the HOPG surface in combination with tungsten tip models of two different apex geometries and 18144 different orientations. We calculate constant-current profiles along the <1100> direction of the HOPG(0001) surface in the |V|≤ 1 V bias voltage range, and compare them with experimental data. We find that a blunt tip model provides better correlation with the experiment for a wider range of tip orientations and bias voltages than a sharp tip model. Such a combination of experiments and large scale simulations opens up the way for obtaining more detailed information on the structure of the tip apex and more reliable interpretation of STM data in the view of local tip geometry effects.