[{"type":"speech","title":"Non-linear electronic transport through a benzene molecule","issued":{"date-parts":[["2002"]]},"author":[{"family":"Wegewijs","given":"M."},{"family":"Hettler","given":"M."},{"family":"Schoeller","given":"H."},{"family":"Wenzel","given":"W."}],"note":"Fr\u00fchjahrstagung des Arbeitskreises Festk\u00f6rperphysik (AKF) der DPG, Regensburg, 11.-15.M\u00e4rz 2002 Verhandlungen der Deutschen Physikalischen Gesellschaft, R.6, Bd.37 (2002) TT 8.4","abstract":"The nonlinear transport through a benzene molecule coupled weakly to electrodes is analyzed theoretically. A negative differential conductance effect (NDC) is predicted. It is caused by the population of a certain excited state of the molecule-anion at a finite bias voltage. This state can spontaneously decay under photon emission to a lower lying state which does not couple to the electron tunneling. Therefore, the flow of current is blocked above the threshold voltage.\nThis effect is linked to the symmetry properties of the molecule with respect to the transport direction and is found to be generic. This may provide a clue for finding molecules with desired current-switching properties.\nFrom electronic structure calculations an effective interacting Hamiltonian for the pi-electrons is constructed which serves as input for a transport calculation. Most importantly, Coulomb blockade effects are accounted for properly. Furthermore, the relevance of diffuse orbitals (so-called Rydberg states) for an extension of the effective model is discussed.","kit-publication-id":"230051259"}]