Effect of torsion angle on electronic transport through different anchoring groups in molecular junction

By applying nonequilibrium Green's function formalism combined with first-principles density functional theory, we investigate effect of torsion angle on electronic transport properties of 4,4′-biphenyl molecule connected with different anchoring groups (dithiocarboxylate and thiol group) to Au(111) electrodes. The influence of the HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the quantum transport through the molecular device are discussed. Theoretical results show that the torsion angle plays important role in conducting behavior of molecular devices. By changing the torsion angle between two phenyl rings, namely changing the magnitude of the intermolecular coupling effect, a different transport behavior can be observed in these two systems.