Regensburg 2016 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 15: STM/AFM: New Approaches

O 15.8: Vortrag

Montag, 7. März 2016, 17:00–17:15, H24

Sub-molecular resolution imaging of molecules by AFM: Pauli versus Coulomb — Joost van der Lit¹, •Nadine J. van der Heijden¹, Francesca Di Cicco¹, Prokop Hapala², Pavel Jelinek², and Ingmar Swart¹ — ¹Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University, Utrecht, The Netherlands — ²Institute of Physics, Academy of Sciences, Prague, Czech Republic

In the past year, the origin of the contrast mechanism responsible for sub-molecular resolution imaging of molecules with functionalized tips has been a point of great discussion [1-3]. Especially the flexibility of the probe contributes to the high spatial resolution. Initially, van der Waals and Pauli interactions were thought to be responsible for the tip bending. Recently, it has been realized that also electrostatic forces influence the contrast [4]. Here, we study the role of the electrostatic force on the tip by imaging strongly polarized molecules with differently polarized tips. The charge on the final atom of the tip can be varied by different tip termination. CO tips yield nearly neutral tips while Xe terminated tips have a slight positive charge. This results in a difference in contrast in the final AFM image. References: [1] P. Hampala, PRB, 80, 085421, (2014). [2] J. Zhang, Science, 342, 611, (2013). [3] S. Hämäläinen, Phys. Rev. Lett. 113, 186102 (2014). [4] P. Hapala, Phys. Rev. Lett. 113, 226101 (2014).