Spintronic and electro-mechanical effects in single-molecule transistors

Abstract

We investigate electron transport through a mixed-valence molecular dimer, where an excess electron is delocalized over equivalent monomers, which can be locally distorted. In this system the Born-Oppenheimer approximation breaks down, resulting in quantum entanglement of the mechanical and electronic motion. We show that this breakdown results in distinct features in the transport spectrum that can be measured in recently developed three-terminal junctions with mechanical control. Additionally, for monomers with fixed localized spins, we show that the interplay of spin and vibrational motion allows the molecular spin parameters to be detected in situ, without an applied magnetic field. Conversely, the spin state of the entire molecule can be controlled via the non-equilibrium quantized molecular vibrations due to a novel vibration-induced spin-blockade. © 2009 Springer-Verlag Berlin Heidelberg.