Transport through a biphenyl system as a function of torsion angle: An effective coupling model approach

We present a non-self-consistent renormalized model to calculate the electron transmission through a single molecule connected to two metallic terminals. The treatment is an improvement of a decimation technique, once all relevant parameters of the model were extracted from ab initio calculations performed for an extended system comprising the molecule sandwiched by two metallic clusters. Moreover, calculations were done for different values of the applied electric field so as to take account changes in the electronic structure due to this field. We applied this approach to describe the electron transport through a system composed of two phenyl rings connected at different torsion angles, with the self-energy modeled at the wideband limit approximation. The proposed model captures the main features of the molecular system and provides a simple interpretation of the charge transport characteristics, and overall, the results are in a general good agreement with the theoretical and experimental data available in the literature.