Determination of diffusion tensors from oscillating and circulating scanning probe tips
1 Fachbereich Physik, Universität Osnabrück - Barbarastraße 7, 49076 Osnabrück, Germany
2 School of Physics & Astronomy, The University of Nottingham, University Park Nottingham NG7 2RD, UK
Received: 11 March 2015
Accepted: 15 June 2015
We develop two methods for determining anisotropic diffusion properties of molecules on surfaces. These methods are based on the analysis of signal fluctuations recorded with moving probe tips, of, for example, a scanning tunneling microscope. In the first method, the probe tip oscillates along a straight line, which allows to quantify the effective diffusion perpendicular to the line. By varying the line orientation, the diffusion tensor is obtained. In the second method, the probe tip rotates along a circle and the diffusion tensor is determined by analysis of cross-correlations between antipodal points. Both methods are successfully validated against surrogate data from kinetic Monte Carlo simulations.
PACS: 68.43.Jk – Diffusion of adsorbates, kinetics of coarsening and aggregation / 68.35.Fx – Diffusion; interface formation / 82.37.Gk – STM and AFM manipulations of a single molecule
© EPLA, 2015