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R. G. Herb Condensed Matter Seminar
Single-Particle Properties of Graphene: Magnetotransport and Superlattice-Controlled Band Gap
Date: Tuesday, March 10th
Time: 10:00 am
Place: 5310 Chamberlin
Speaker: Rakesh Tiwari, Ohio State University
Abstract: Graphene, a two-dimensional form of carbon, is poised to play an important role in future electronic devices. In this talk I will discuss two properties of graphene which may be very useful for next-generation devices: large magnetoresistance and the controllable band gap at the Dirac point. I will show that the experimentally observed large magnetoresistance can be explained using a picture of graphene as a mixture of n and p type puddles. Even if we assume a field independent resistivity for the individual puddles (free electron or hole picture), an effective medium approximation predicts a large magnetoresistance for the composite, in agreement with experiment. In the second part of the talk, I will describe an efficient way of controlling the electronic band gap at the Dirac point in graphene using a non-centrosymmetric superlattice potential. I will confirm this method by calculating the superlattice band structure using an expansion of the wave functions in plane waves.
Host: Robert Joynt
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