Phonon-Rabi-Resonance and Assisted Tunneling in Molecules

Transport through nanoscopic systems with strong electron interactions, such as atoms, molecules, and quantum dots, has received increasing attention. It is known that electron-electron (EE) and electron-phonon (EP) interactions have non-trivial effects on the transport properties of these systems. However, relatively little is known about the {\em joint} effect of EE and EP interactions, and one expects new transport properties in systems within this regime. We study a model for a system of two quantum dots connected to two independent leads. Electron hopping between the dots is accompanied by phonon emission or absorption. We use the equations of motion to calculate electronic Green's functions and relevant transport properties. We find that Coulomb repulsion modifies the usual resonant condition, and phonon energy and electron level spacing in the dots are no longer matched. The new resonant condition involves an energy scale arising from EE interactions for partially or fully occupied sites, {\em irrespective of inter-site correlations}. We also find that Coulomb blockade peaks in resonance exhibit Rabi-like splittings in the conductance. These effects are strongly affected by temperature, which would be a clear experimental signature of the effect. \newline \newline Supported by CAPES-Brazil and NSF-IMC and NSF-NIRT.