The transport properties of graphene—a two-dimensional sheet of carbon atoms—deviate significantly from those of conventional materials. In addition, special fabrication techniques that shape graphene into ribbons can reduce the effective dimensionality of graphene to that of a quasi-one-dimensional system.
The hope is that with graphene ribbons one could make contact with the one-dimensional world where electronic correlations give rise to unusual effects. In a Rapid Communication published in Physical Review B, Yu-Ming Lin, Vasili Perebeinos, Zhihong Chen, and Phaedon Avouris from the IBM T. J. Watson Research Center have reported the experimental observation of a signature of one-dimensional transport in 30-nm-wide graphene ribbons: by controlling the carrier density, they observe discrete, evenly spaced conductance plateaus in the current-versus-voltage response. This behavior, which they interpret as evidence of conductance quantization, does not occur in purely two-dimensional graphene.
Although the effects of scattering from impurities and the rough edges of the ribbon remain to be clarified, the observations reported in the paper will undoubtedly lead to further theoretical and experimental studies in a subject of continuing interest. – Alexios Klironomos