Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 57: New Methods: Theory
O 57.3: Talk
Wednesday, March 20, 2024, 16:45–17:00, MA 043
STM simulations with asymmetric/tilted tips: the case of Cu and CO on Cu(111) — Ivan Abilio1,2 and •Krisztián Palotás1,2 — 1Wigner Research Center for Physics, Budapest, Hungary — 2Institute of Physics, Budapest University of Technology and Economics, Budapest, Hungary
The correct interpretation of experimental scanning tunneling microscopy (STM) images is very important. The presence of asymmetric/tilted tips complicates this procedure and results in reduced symmetry of the STM images. There are only a few theoretical methods, which are able to treat arbitrary tilting of the tip in STM simulations [1,2,3,4]. In the present work, we employ the revised Chen’s derivative rules [4] to study the effect of tilted tips on the STM imaging of a Cu adatom and a CO molecule on a Cu(111) surface. Apart from obtaining good agreement with published experimental images [5], our method enables an analysis of the tunneling current in terms of tip orbital contributions, and thus provides a deeper theoretical understanding of the STM contrast formation. We point out important differences between pure and CO-functionalized metal (symmetric and tilted) STM tips. [1] G. Mándi et al., J. Phys. Condens. Matter 25, 445009 (2013). [2] G. Mándi et al., J. Phys. Condens. Matter 26, 485007 (2014). [3] G. Mándi et al., Prog. Surf. Sci. 90, 223 (2015). [4] G. Mándi and K. Palotás, Phys. Rev. B 91, 165406 (2015). [5] A. Gustafsson et al., Phys. Rev. B 96, 085415 (2017).
Keywords: scanning tunneling microscopy (STM); simulation; tilted tip, functionalized tip; carbon monoxide; copper