Berlin 2015 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 28: Moire and Graphene Stacking

O 28.8: Vortrag

Dienstag, 17. März 2015, 15:45–16:00, MA 041

Electronic Conductivity of Twisted Bilayer Graphene — •Nicolas Ray, Sam Shallcross, and Oleg Pankratov — Lehrstuhl für theoretische Festkörperphysik, Universität Erlangen-Nürnberg, Staudtstr. 7 B2, 91058 Erlangen, Germany

The electronic structure of a graphene twist bilayer in the small angle limit is characterized, for states near the Dirac point, by electron localization on the moire lattice and by a significant suppression of the band velocities [1]. This should lead to significant (and rotation angle dependent) changes of the bilayer conductivity. We explore this question within the low energy theory of the electron spectrum, and employing the linearized Boltzmann equation for the transport calculations [2]. We examine the scattering probabilities and the conductivity as functions of the twist angle, the doping level and the temperature. Our results show a dramatic decrease of the conductivity of a weakly doped bilayer with decreasing twist angle.

[1] S. Shallcross et al., Phys. Rev. B 87, 245403 (2013); [2] E. Mariani et al., Phys. Rev. B 86, 165448 (2012).