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L. Chizhova, F. Libisch, J. Burgdörfer:
"Magneto-optical response of graphene on boron nitride: Dirac cone replica and Excitonic effects";
Poster: International Winterschool on Properties of Novel Materials (IWEPNM) 2015, Kirchberg in Tirol; 07.03.2015 - 14.03.2015.

Optical transitions between Landau levels provide precise information on the electronic structure of graphene, as well as substrate and many-body effects. In this work we calculate the magneto-optical response (optical conductivity) of large-size graphene flakes aligned on hexagonal boron nitride (BN) using a tight-binding approach. Recent experiments reveal satellite band gaps in the density of states away from the Dirac point induced by the BN substrate. These structures were interpreted as secondary Dirac cones. However, our calculations suggest that the satellites feature parabolic dispersion and the difference in interpretation arise as an artifact of measuring as a function back gate voltage [1]. We propose magneto-spectroscopy as a way to probe the satellite and Dirac Landau levels in terms of energy. In addition we include the magneto-excitonic correction to the main transition lines in first order perturbation theory. Our approach yields a quantitative explanation of recently observed Landau-level dependent renormalizations of the Fermi velocity.
[1] L.A. Chizhova, F. Libisch, and J. Burgdörfer PRB 90 (2014) 165404

Graphene, Boron Nitride, Moire Structure, Optical Response