Single-molecule field-effect transistors: A computational study of the effects of contact geometry and gating-field orientation on conductance-switching properties

The relation of geometric features to the effect of gating electric fields on the conductance through conjugated systems is investigated by electronic transmission calculations employing Green’s function based modeling. Switching is only induced if the field is applied in an orientation which results in energy shifting of the molecular orbitals. This is found to depend on the orientation of the field with respect to the plane defined by the molecular conjugation. The switching can be quenched by structural rearrangement of the chemical bonds to the bulk, where the relative position of the electrodes is modified.