Electronic transport through single molecules: effects of strain and contacts

We will present theoretical investigations on single-molecule electron transport. We will focus on the following systems: a) Connected Au nanoparticles: we performed a first principles study [1] of the electronic properties of lattices of Au nanoparticles functionalized by the conjugated molecules BDMT and BDCT. Distinct behaviors of the electron hopping matrix elements between particles as a function of compression are predicted for functionalized lattices. b) Current rectification with symmetric molecules: In an interesting experiment, Reichet et al. [2] measured the current through symmetric organic molecules and obtained asymmetric IV curves when the Au contacts are pulled apart. We show, by means of first-principles calculations, that this effect can originate from the formation of small Au chains between the molecule and the Au surfaces in an asymmetric way. [1] R. J. C. Batista et al, Phys. Rev. Lett. 96, 116802 (2006). [2] J. Reichet et al., Phys. Rev. Lett. 88, 176804 (2002).