Combined effect of magnetic and electric fields on Landau level spectrum and magneto-optical absorption in bilayer graphene

National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University Nanjing 210093, China

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b gjin@nju.edu.cn

Received: 6 May 2010
Accepted: 15 November 2010

Abstract

We theoretically study the Landau level spectrum of a graphene bilayer subjected to a magnetic field and an electric field simultaneously. From the analytic expressions obtained, we can controllably modulate the Landau level structure by applying external fields. We also give an explicit criterion for determining the crossing of different Landau levels in the graphene bilayer. For providing a scheme of experimental verification, we investigate further the intraband magneto-optical absorption in such a biased bilayer. It is found that the optical absorptions between adjacent Landau levels in the system are strongly dependent on the combination of applied magnetic and electric fields. Particularly, the optical absorption peaks can exhibit first red-shift and then blue-shift with the reversion of orders of peaks, and even at the specific combinations of magnetic and electric fields some typical absorption peaks vanish.