Non-equilibrium Green’s functions method in matrix representation. 3. Huckel model of graphene

Authors: Kruglyak Yu.A., Kryzhanovskaya T.V.

Year: 2016

Issue: 20

Pages: 121-127


Non-equilibrium Green’s functions method is applied to graphene, using the nearest neighbor orthogonal tight-binding model in the frame of the «bottom – up» approach of modern nanoelectronics. There is also a general method to account for electric contacts in Schrödinger equation in order to solve electron quantum transport problems given.
As an illustrative example of the calculation results for the transmission coefficients and the density of states in Huckel model the graphene ribbons are computed in two boundary configurations – Zigzag and Armchair Graphene Nanoribbons. The calculations were performed for ribbons with width of 53 nm and with resonance integral 2.7 eV. Noteworthy is the high density of states at E = 0 for a zigzag configuration of a graphene ribbon. These are so-called edge local states near the Fermi level that are not available in Armchair configuration. It is worth to note the high plausibility of the results obtained even within such a simple model of graphene as in strong-coupling approximation in orthogonal parametric basis with account of the interaction of neighboring atoms only.

Tags: graphene; nanoelectronics; nanophysics; NEGF method; transmission coefficient


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