Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 37: MLT: Poster Session

TT 37.24: Poster

Donnerstag, 25. März 2010, 14:00–18:00, Poster A

Bistability and oscillatory motion of natural nano-membranes appearing within monolayer graphene on silicon dioxide investigated by scanning tunneling microscopy — •Marco Pratzer, Torge Mashoff, Viktor Geringer, Marcus Liebmann, and Markus Morgenstern — II. Physikalisches Institut B and JARA-FIT, Otto-Blumenthal-Straße, RWTH Aachen, 52074 Aachen

The truly two-dimensional material graphene is an ideal candidate for nanoelectromechanics due to its large strength and mobility. Monolayer graphene flakes were prepared by mechanical exfoliation on a SiO₂ substrate. Using scanning tunneling microscopy at T=4.8 K we found natural nano-membranes within the intrinsic rippling of the graphene with a size down to 3 nm. The membranes could be lifted either reversibly or hysteretically by the tip of the scanning tunneling microscope depending on the interacting forces of substrate, graphene and tip. Atomically resolved STM images show different atomic arrangements in compressed and relaxed graphene areas. The clamped-membrane model including van-der-Waals and dielectric forces explains the results quantitatively. By applying an AC bias voltage we could oscillate the nano-membranes, which might lead to a completely novel approach to controlled quantized oscillations or single atom mass detection.