Computation of the I/V characteristic of a molecular switch

We report on the study of a molecular torsional switch made up of two distinct aromatic moieties bound by an acetynil group. The mechanism of operation is based on the action of a static electric field perpendicular to the ring - ring bond which modifies the torsional angle and, as a consequence, the inter-ring conjugation. The current is computed with a method based on the molecular Green's function, in which the electrodes are taken into account in an effective way. The current/ voltage profile at several dihedral angles shows that the current is maximum for the planar conformation and decreases by a factor ∼1000 for the orthogonal conformation, suggesting the potential applicability of the proposed switching function in devices at the molecular scale.