Dresden 2014 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 111: Graphene: Bi- and multi-layers (with MA/O/TT)

HL 111.2: Talk

Friday, April 4, 2014, 09:45–10:00, POT 081

Study of the magnetoresistance of biased graphene bilayers — •Dmitri Smirnov¹, Galina Y. Vasileva^1,2, Yurij B. Vasilyev², Pavel S. Alekseev², Yurij L. Ivanov², Hennrik Schmidt¹, Alexander W. Heine¹, and Rolf J. Haug¹ — ¹Institut für Festkörperphysik, Leibniz Universität Hannover — ²Ioffe Physical Technical Institute, Russian Academy of Sciences, St. Petersburg

We demonstrate magnetotransport behaviour of bilayer graphene. In contrast to monolayer graphene, bilayer has a parabolic band structure with a zero band gap, which can be opened by applying an electrical field perpendicular to the samples [1]. One of the consequences of such a band structure is the coexistence of two different types of charge carriers with the Fermi energy placed near the charge neutrality point.

Several bilayer graphene samples with different electrical properties (charge neutrality point, mobility) have been investigated. A positive and negative magnetoresistance is observed for electrons and holes. We can show that that the positive magnetotransport can be described well with a two carrier Drude model which allows us a new approach to probe parameters of electrons and holes separately.

[1] McCann, E., and V. Fal’ko Phys. Rev. Lett. 96, 086805 (2006)