First-Principles Study on Electron-Conduction Properties of C${}_{60}$ Chains

The electron-conduction properties of fullerene chains are examined by first-principles calculations based on the density functional theory. The conductivity of the C${}_{60}$ dimer is low owing to the constraint of the junction of the molecules on electron conduction, whereas the C${}_{60}$ monomer exhibits a conductance of $\sim$ 1 G${}_0$. One of the three degenerate $t_{u1}$ states of C${}_{60}$ is relevant to conduction and the contributions of the others are small. In addition, we found a more interesting result that the conductance of the fullerene chain is drastically increased by encapsuling metal atoms into cages.