The aim of the project is to achieve an improved understanding of charge transport through flexible organic molecular junctions between two leads. We focus on the interplay between the charge flow across the molecules and their torsional degrees of freedom. We will study in particular, how the conformational changes of the molecules (from the torsional motion or from charging effects) determine intra-molecular couplings and thereby dynamically affect the conductance. We will further study whether specific molecular side groups with an intrinsic dipole moment can be used to steer (e.g. by an external gate) the molecular conformation and thereby the current. For (-conjugated molecules, such as triphenyl, we will address the crossover from coherent quantum transport to single-electron tunneling starting from two complementary approaches, non-equilibrium Green function techniques and a generalized master equation approach (including coherences) for the reduced density matrix. We will employ both (realistic) model Hamiltonians, including electron correlations effects, as well as, in cooperation with other groups from the priority program, DFT-based and quantum chemistry calculations.
