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External Bias Dependent Direct To Indirect Band Gap Transition in Graphene Nanoribbon

Majumdar, Kausik and Murali, Kota VRM and Bhat, Navakanta and Lin, Yu-Ming (2010) External Bias Dependent Direct To Indirect Band Gap Transition in Graphene Nanoribbon. In: Nano Letters, 10 (8). pp. 2857-2862.

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Official URL: http://pubs.acs.org/doi/abs/10.1021/nl100909n

Abstract

In this work, using self-consistent tight-binding calculations. for the first time, we show that a direct to indirect band gap transition is possible in an armchair graphene nanoribbon by the application of an external bias along the width of the ribbon, opening up the possibility of new device applications. With the help of the Dirac equation, we qualitatively explain this band gap transition using the asymmetry in the spatial distribution of the perturbation potential produced inside the nanoribbon by the external bias. This is followed by the verification of the band gap trends with a numerical technique using Magnus expansion of matrix exponentials. Finally, we show that the carrier effective masses possess tunable sharp characters in the vicinity of the band gap transition points.

Item Type: Journal Article
Additional Information: Copyright of this article belongs to American Chemical Society.
Keywords: Graphene;nanoribbon;bandgap;tight-binding method;effective mass.
Department/Centre: Division of Electrical Sciences > Electrical Communication Engineering
Others
Date Deposited: 06 Sep 2010 10:56
Last Modified: 19 Sep 2010 06:15
URI: http://eprints.iisc.ernet.in/id/eprint/31968

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