Dresden 2009 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 26: Nanostructured Materials I
MM 26.4: Vortrag
Mittwoch, 25. März 2009, 11:00–11:15, IFW B
Conductivity and shot noise in graphene at high bias voltages — •Aurelien Fay1, Romain Danneau1,2, Fan Wu1, Matti Tomi1, Julien Wengler1, and Pertti Hakonen1 — 1Low Temperature Laboratory, Helsinki University of Technology, Espoo, Finland — 2Institut für Nanotechnology, Forschungszentrum Karlsruhe, and Physikalische Institut, Universität Karlsruhe, Karlsruhe, Germany
The conductivity and the shot-noise in graphene contain both interesting informations on the transport properties of the Dirac fermions. By measuring these two quantities, we have shown that the transport in Graphene could be ballistic [1]. The interaction between optical phonons and charge carriers in graphene can suppress this ballistic transport and, therefore, dramatically changes the conductivity and the Fano factor.
We have increased the electron-phonon coupling in graphene by subjecting the graphene sample at high bias voltages [2]. At a relative low bias, we have measured a linear dependence of the conductivity as a function of the bias voltage. This has been recently pointed out by E. Sonin [3]. In the high bias regime, the decrease of the conductance and the drop of the Fano factor could both be explained by the interaction between optical phonons and charge carriers.
[1] R. Danneau et al., Phys. Rev. Lett. 100, 196802 (2008).
[2] W.K. Tse et al, Appl. Phys. Lett. 93, 023128 (2008)
[3] E. B. Sonin, Phys. Rev. B 77, 233408 (2008).