Regensburg 2016 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 7: Graphene I: Structure and Dynamics
O 7.1: Vortrag
Montag, 7. März 2016, 10:30–10:45, H24
The electronic structure of graphene superlattices revisited — •Pilkwang Kim1 and Cheol-Hwan Park2 — 1Department of Physics and Astronomy, Seoul National University, Seoul, Korea — 2Department of Physics and Astronomy, Seoul National University, Seoul, Korea
We present the calculated electronic structure of graphene superlattices, which are graphenes under lateral, periodic potential. Previous studies on a graphene superlattice [1-3] have reported anisotropic group velocity renormalization, emergence of new zero-energy points, conductance resonance, etc. However, several features manifested in the electronic structure obtained from our numerical calculations, e.g., the movement of the Dirac points in momentum space, cannot be explained by the theories introduced in those studies. In this presentation, we discuss the reason why there are features in the electronic structure of graphene superlattices that were not captured by previous theories. We also discuss electronic structure obtained by using first- and higher-order perturbation calculations.
1.Park, C.-H., Yang, L., Son, Y.-W., Cohen, M. L. & Louie, S. G. New generation of massless Dirac fermions in graphene under external periodic potentials. Phys. Rev. Lett. 101, 126804 (2008). 2.Barbier, M., Vasilopoulos, P. & Peeters, F. M. Dirac electrons in a Kronig-Penney potential: Dispersion relation and transmission periodic in the strength of the barriers. Phys. Rev. B 80, 205415 (2009). 3.Brey, L. & Fertig, H. A. Emerging Zero Modes for Graphene in a Periodic Potential. Phys. Rev. Lett. 103, 046809 (2009).