Transport model with atomistic band structure of graphene nanoribbon

Abstract

The aim of the paper is to study the ballistic quantum transport in armchair graphene nanoribbon by developing a transport model followed by subsequent simulation. Electron transport in nanodevices can be studied by two different methods viz. wave function method and non-equilibrium Green function method. Here, we use the wave function method based transport mechanism with a view point on an atomistic quantum modeling of band structure. The interaction effects, unlike in Green function method, are included in a semi-empirical way where the resulting parameters are evaluated by fitting to experimental results. Interesting finding hitherto unknown to the graphene community, to the best belief of the authors, is that the current in armchair graphene nanoribbon starts to conduct only from a definite channel which is very much dimension-specific. As example, current conduction observed in the ribbon of dimension of seven atoms width starts only from the second channel. It is also noticed that a width dependent bandgap manifests the armchair ribbon to behave both as a semiconductor and semimetal depending on which family the ribbon belongs to. Further, the conductance of the ribbon is seen to have plateaus and current in it rises up in steps with increase of bias.