Thermoelectric properties of vibrating molecule asymmetrically connected to the electrodes

Here we present a theoretical analysis of inelastic effects on the thermoelectric properties of molecular-scale junction in both linear and nonlinear response regimes. Considered device is composed of molecular quantum dot (with discrete energy levels) asymmetrically connected to metallic electrodes (treated within the wide-band approximation) via potential barriers, where molecular vibrations are modeled as dispersionless phonon excitations. Nonperturbative computational scheme, used in this work, is based on Green's function theory within the framework of polaron transformation (GFT-PT), which maps the many-body electron-phonon interaction problem into a one-body multi-channel single-electron scattering problem. It is shown that all the thermoelectric characteristics are dominated by the quantum transport of virtual polarons due to a strong electron-phonon coupling. (c) 2006 Elsevier B.V. All rights reserved.