What we can learn from high-resolution Scanning Probe images of graphene and organic molecules, Dr. Pavel Jelinek (Uni Prag)

20.01.2015 von 17:00 bis 18:00

Einladender: Prof. Berndt

What we can learn from high-resolution Scanning Probe images of graphene and organic molecules: from nanoelectronics to the origin of Life

Dr. Pavel Jelinek, Institute of Physics of the AS CR, Prague

Scanning Probe Microscopy provided unprecedented atomic resolution of single molecules or surface defects in real space. Here we will show how combined experimental and theoretical studies can bring new understanding of diverse phenomena.

In first part of the talk, we will discuss a novel way for single-atom substitutional doping of graphene. Nitrogen doping [1] is probably one of the most extensively studied routes to tune the electronic properties of pristine graphene. Here we report a straightforward method to produce high-quality nitrogen [2] and boron-doped graphene grown on SiC(0001).

We also show that graphene can play fundamental role to explain the origin of polyaromatic hydrocarbon molecules in the universe [3]. In second part, we will discuss high-resolution images of single organic molecules obtained with Atomic Force Microscopy (AFM) [4] and Scanning Tunneling Microscopy

(STM) [5] using functionalized tips. Here we will present 3D maps of the force, tunneling current and dissipation over a monolayer of PTCDA molecules deposited on Ag(111) acquired at 1.2 Kelvin with Xe-functionalized tip. We will compare detailed contrast features of the force maps at various tip-sample separations to a numerical model [6]. Combing the experimental and theoretical evidence, we will explain the high-resolution imaging mechanism, artifacts and a possibility to map out intra-molecular charge distribution in realspace.

[1] L. Zhao et al Science 333, 999, (2011).

[2] M. Telychko et al ACS Nano 8, 7318 (2014).

[3] P. Merino et al Nature Comm. 5, 3054 (2014).

[4] L. Gross et al., Science 325,1110 (2009).

[5] R. Temirov et al., New. J. Phys.10, 053012 (2008).

[6] P. Hapala et al., Phys. Rev. B 90, 085421 (2014); P. Hapala et al. Phys. Rev. Lett. 113, 226101 (2014).

Der Vortrag findet um 17:00 Uhr im Hans-Geiger-Hörsaal (LS13-R.52) des Physikzentrums statt.

Ab 16:45 Uhr werden Kaffee und Gebäck angeboten.

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