The signatures of truly molecular mediated quantum transport in single molecule experiments have to be selectively identified and often their theoretical mechanisms still need to be understood. We investigated the behavior of a donor-acceptor molecular junction in the coherent regime using a model Hamiltonian [1] as well as density functional based nonequilibrium transport calculations [2]. Additionally, we studied the system in the situation of weak coupling to the leads where charging effects do play an important role and we could show that the intrinsic energetic asymmetry of a donor-acceptor molecule remains responsible for the rectification effects even in the Coulomb blockade regime [3]. Contact to the experiments by Elbing et al. [4] is also provided.
[1] F. Pump and G. Cuniberti, cond-mat/0611436.
[2] F. Pump et al., in preparation.
[3] B. Song, D. Ryndyk, and G. Cuniberti, cond-mat/0611190.
[4] M. Elbing et al., Proc. Natl. Acad. Sci. USA 102, 8815 (2005).