Thermoelectric effects in molecular quantum dots with contacts

Abstract

We consider the steady-state thermoelectric transport through a vibrating molecular quantum dot that is contacted to macroscopic leads. For moderate electron-phonon interaction strength and comparable electronic and phononic timescales, we investigate the impact of the formation of a local polaron on the thermoelectric properties of the junction. We apply a variational Lang-Firsov transformation and solve the equations of motion in the Kadanoff-Baym formalism up to second order in the dot-lead coupling parameter. We calculate the thermoelectric current and voltage for finite temperature differences in the resonant and inelastic tunneling regimes. For a near resonant dot level, the formation of a local polaron can boost the thermoelectric effect because of the Franck-Condon blockade. The line shape of the thermoelectric voltage signal becomes asymmetrical due to the varying polaronic character of the dot state and in the nonlinear transport regime, vibrational signatures arise.

11 pages, 4 figures, final version

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Cited by in corpus (14)

• Phonon-thermoelectric transistors and rectifiers
• Nonlinear phenomena in quantum thermoelectrics and heat
• Electron transfer across a thermal gradient
• Electron transfer at thermally heterogeneous molecule-metal interfaces
• Effects of electron-phonon interaction on thermal and electrical transport through molecular nano-conductors
• Electrothermal Transistor Effect and Cyclic Electronic Currents in Multithermal Charge Transfer Networks
• Thermodynamics of the polaron master equation at finite bias
• Thermoelectric transport through a quantum nanoelectromechanical system and its backaction
• Energy Transfer and Thermoelectricity in Molecular Junctions in Non-Equilibrated Solvents
• Thermally induced charge current through long molecules
• Quantum thermocouples: nonlocal conversion and control of heat in nanostructures
• Nonlinear thermoelectric transport in single-molecule junctions: the effect of electron-phonon interactions
• Heating and thermoelectric transport in a molecular junction
• Charge density wave breakdown in a heterostructure with electron-phonon coupling