Anomalous I–V curve for mono-atomic carbon chains

The electronic transport properties of mono-atomic carbon chains were studied theoretically using a combination of density functional theory and the non-equilibrium Green’s functions method. The I–V curves for the chains composed of an even number of atoms and attached to gold electrodes through sulfur exhibit two plateaus where the current becomes bias independent. In contrast, when the number of carbon atoms in the chain is odd, the electric current simply increases monotonically with bias. This peculiar behavior is attributed to dimerization of the chains, directly resulting from their onedimensional nature. The finding is expected to be helpful in designing molecular devices, such as carbon-chain-based transistors and sensors, for nanoscale and biological applications. S Online supplementary data available from stacks.iop.org/NJP/12/103017/ mmedia Carbon-based nanostructures spanning different dimensionalities, going from two-dimensional (2D) graphene, to quasi-1D nanotubes, to quasi-zero-dimensional fullerenes, have already shown their potential for the case of a broad range of applications. These include molecular devices, fuel cells and structural/functional composites for bioand nano-technology. As such they have inspired extensive studies, both experimental and theoretical [1]–[4]. Recently, a new kind of nanostructure, named mono-atomic carbon chains (MACCs), was experimentally produced by pulling out C atoms row by row from graphene [5]. In contrast with the abovementioned nanostructures, MACCs have truly 1D features since their radius is minimal for carbon and each C atom neighbors only two other C atoms. Consequently, due to their small size, 3 Authors to whom any correspondence should be addressed. New Journal of Physics 12 (2010) 103017 1367-2630/10/103017+09$30.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft