Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 28: Moire and Graphene Stacking
O 28.3: Vortrag
Dienstag, 17. März 2015, 14:30–14:45, MA 041
Scanning Probe Microscopy Study of Moiré Patterns on Rotated Graphene Layer on Highly Oriented Pyrolytic Graphite — •Dilek Yildiz1,2, Şener Şen3, Marcin Kisiel1, Oğuz Gülseren3, Ernst Meyer1, and Oğuzhan Gürlü2 — 1University of Basel, Basel, Switzerland — 2Istanbul Technical University, Istanbul, Turkey — 3Bilkent University, Ankara, Turkey
Highly Oriented Pyrolytic Graphite (HOPG) has weak van der Waals interaction between its layers so they can be cleaved easily and fresh (0001) graphite surfaces can be obtained. As another result of this weak interaction, the topmost graphene layer can be rotated with respect to the rest of the crystal and super periodic structures called as moiré patterns are formed. Such moiré patterns were extensively studied by Scanning Tunneling Microscopy (STM) and Spectroscopy (STS). In this study, we investigate the morphological and electronic properties of moiré patterns on HOPG by using STM and STS under ambient conditions. Apparent corrugation changes of different moiré patterns were studied as a function of the bias voltage. We studied the electronic properties of moiré patterns with respect to their periodicities. Van Hove singularities were observed on moiré patterns in STS data and their origin were clarified by means of ab initio calculations. Observation of moiré patterns by Atomic Force Microscopy (AFM) is yet to be reported on HOPG surfaces. In our recent studies we are interested in the frictional properties of varying moiré patterns on HOPG. Our particular interest is to observe the frictional response of the moiré patterns to the tip perturbation by use of pendulum geometry AFM.