A minimalistic diode
  In this paper we present a minimalistic model sufficient for current asymmetries in molecules. In particular, we search for an interaction on the molecule which causes current asymmetries independent of additional assumptions or the precise form of its environment. To this end we first discuss earlier proposals and clarify the importance of additional assumptions. We then present a minimal model of a strongly polarizable molecule which shows a strongly asymmetric I/V calculated within time dependent DMRG. 
Tim Collet, Peter Schmitteckert
cond-mat.mes-hall