Electronic Excitations of a Single Molecule Contacted in a Three-Terminal Configuration

Low-temperature three-terminal transport measurements through a thiol end-capped pi-conjugated molecule have been carried out. Electronic excitations, including zero and finite-bias Kondo-effects, have been observed and studied as a function of magnetic field. Using a simplified two-orbital model, we have accounted for the spin and the electronic configuration of the first four charge states of the molecule. The charge-dependent couplings to gate, source, and drain electrodes suggest a scenario in which charges and spins are localized at the ends of the molecule, close to the electrodes.