Electronic properties of carbon nanoribbons and peculiar width dependence

We make a systematic analysis of the electronic properties of a wide class of carbon nanoribbons, characterizing them by edge shape and width. Carbon nanoribbons are one-dimensional aromatic compounds akin to nanotubes. They exhibit a rich variety of band gaps, from metals to typical semiconductors. The band gaps of several nanoribbons form a valley structure with stream-like sequences of metallic or almost metallic nanoribbons. We find that the band gaps of armchair and chiral nanoribbons oscillate as a function of the width, and take local minima almost at the same values of the width w for any q. Furthermore a possible application of nanoribbons to nanoelectronics is discussed.