First-principles electronic transport properties study of small carbon clusters: Cyclic C6

The transport properties of the six-atom carbon ring cluster C6 sandwiched between Al(100) electrodes have been investigated by first-principles nonequilibrium Green's function technique. Our results demonstrate that the transport properties of monocyclic C6 with D3hD3h symmetry, with alternating bond angles, the most stable C6 isomer, show metallic conductance. The charge transfer between the central molecule and the electrodes is very important for its transport properties. We also compare the equilibrium transmission spectra for C6 in different isomers.