Berlin 2018 – scientific programme
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O: Fachverband Oberflächenphysik
O 85: Poster: Tribology and Misc.
O 85.7: Poster
Wednesday, March 14, 2018, 18:15–20:30, Poster A
Simulation of STM images and spectroscopy of molecules on metal surfaces: DFTB+ computational platform — •Seddigheh Nikipar1, Dmitry A. Ryndyk1,2, Bálint Aradi2, Francesca Moresco1, Gianaurelio Cuniberti1, and Thomas Frauenheim2 — 1Institute for Materials Science and Center for Advancing Electronics Dresden, TU Dresden, Dresden, Germany — 2Bremen Center for Computational Materials Science, Department of Physics, Universität Bremen, Bremen, Germany
We developed a theoretical and computational approach for simulations of STM images and spectroscopy, in particular of molecules on metal surfaces. We employed the DFT based atomistic tight-binding model (DFTB approach) combined with the Green function technique, which offers a framework to consider a tip, molecule and surface as one integrated system and taking into account the tip geometry. Besides, it captures the interference and interaction effects. This new computational approach can be applied for the investigation of finite-voltage effects and describe the higher molecular transport states. It allows to calculate the tunneling current between a tip and a molecule more precisely, and simulate quantitatively dI/dV maps and spectroscopy curves. We developed the extension of the DFTB+ computational package (dftbplus.org), which makes possible and convenient calculations for large-scale molecular nanosystems on metall surfaces. Our approach is quite fast due to the DFTB approximation and the effective MPI parallelization. The DFTB+ is free software and can be used at HPC clusters.