We present results of spin-unrestricted first-principles quantum transport for a gated ${\mathrm{C}}_{60}$ molecule weakly contacted to Al electrodes, making emphasis on the role played by the electronic localization. As expected, the conductance presents a series of peaks as a function of a gate voltage whenever the charge in the molecule changes by one, demonstrating that transport in the Coulomb blockade regime can be properly treated within a first-principles scheme. A well-known manifestation of the interplay between Coulomb interaction and the spin degree of freedom in atoms and molecules, the Hund’s rule, determines the sequence of conductance peaks.

• Received 23 May 2005

DOI:https://doi.org/10.1103/PhysRevB.72.125424