Dresden 2011 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 51: Graphene III

O 51.2: Vortrag

Mittwoch, 16. März 2011, 15:15–15:30, WIL B321

Local transport measurements on folding graphite and multi-layer graphene on SiO2 by a four-probe scanning tunneling microscope — •Shiro Yamazaki, Tobias Spitz, Oswald Pietzsch, and Roland Wiesendanger — Institute of Applied Physics, University of Hamburg, Germany

Unique electrical transport properties of carbon-based materials such as graphite and graphene have attracted great research interest over a long period of time [1,2]. Mechanically-exfoliated microscopic graphite and multi-layer graphene on SiO2 exhibit sub- micron-scale unique structural defects such as various kinds of layer folding. We have measured the local electrical resistance at folding sites, using a variable-temperature UHV-based four-probe scanning tunneling microscope equipped with a high-resolution UHV scanning electron microscope. We have succeeded in detecting the electrical current flowing along a graphite folding sheet. The folding part exhibits a higher resistance than flat areas. We changed a square-like folding to a triangle-like one by mechanically pushing the tip toward the folding part. The electrical resistance has been compared before and after the manipulation of the folding. [1] K. Krishnan et al., Nature 144, 667 (1939); [2] K. S. Novoselov et al., Nature 438, 197 (2005).