Pair Tunneling and Shot Noise through Molecular Transistor

We theoretically investigate the electronic transport through single

molecules when their vibrational modes are strongly coupled to the

charge degree of freedom and electron pairs are energetically favored to

single electrons. Based on a particle-hole transformation we give a

clearer physical interpretation of the cotunneling and the pair

tunneling in terms of spin preserving and spin-flip cotunneling events

in the transformed model. Within this new scheme we derive the current

and the shot noise characteristics that reveal new features.