Dresden 2014 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 36: Posters: Bio/organic Molecules on Surfaces, Graphene, Solid/liquid interfaces, Metal Substrates, Electronic Structure Theory
O 36.56: Poster
Dienstag, 1. April 2014, 18:30–22:00, P1
An STM-study on the Electronic Properties of epitaxial Graphene using Thermovoltage Effects — •Philip Willke1, Thomas Druga1, Alexander Schneider2, and Martin Wenderoth1 — 1IV. Physikalisches Institut, Georg-August Universität Göttingen, Germany — 2Lehrstuhl für Festkörperphysik, FAU Erlangen, D-91058, Germany
We study the electronic properties of epitaxial-grown mono- and bilayer graphene on SiC by locally mapping the thermovoltage: This quantity is obtained by compensating a finite current present due to the temperature difference between sample and tunneling tip by adjusting the tip-sample voltage. According to theory, this property is sensitive to the change in LDOS at the Fermi level. [1] Recently, it was demonstrated that thermovoltage experiments on epitaxial-grown graphene can be used to distinguish between different domain structures induced by wrinkles. [2] By mapping the thermovoltage in a low-temperature STM operating at 6 K, we can comfirm the theoretical predictions given in [1] by comparing high-resolution spectroscopy and thermovoltage measurements. Moreover, we obtain information on the electron scattering behaviour on monolayer and bilayer graphene with the help of Fourier spectroscopy and we can also identify irregularities in the interface layer. This work was supported by SPP 1459 "Graphene".
[1] J. A. Stovneng and P. Lipavsky, Phys. Rev. B 42, 9214-9216 (1990)
[2] J. Park et al., Nanoletters 13(7) 3269-3273 (2013)