Gate-tunable band-gap in bilayer graphene devices
Abstract
The existence of energy bands for electrons propagating in periodic potentials is arguably the most fundamental implication of quantum mechanics for solid state physics, and is the cornerstone of semiconductor technology. A crucial aspect of the band structure, e.g. in device applications, is the presence of a gap separating valence and conduction band where no states for electrons are available. In general, the presence of a band-gap is determined by the material structure. Here we show that in bilayer graphene, in which no gap is usually present, a gap can be opened without affecting the material structure, simply by applying an electric field perpendicular to the bilayer. We use this capability in nano-electronic devices equipped with gate electrodes to controllably switch off transport through a graphene bilayer. This result represents the first step towards the realization of electrostatically controlled graphene-based devices such as transistors, quantum point contacts and quantum dots.Keywords
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