Thermoelectric properties of vibrating molecule asymmetrically connected to the electrodes

TL;DR

This paper presents a theoretical study of how inelastic effects, especially due to electron-phonon interactions, influence the thermoelectric properties of asymmetrically connected molecular junctions, using advanced Green's function techniques.

Contribution

It introduces a nonperturbative Green's function approach within the polaron transformation framework to analyze inelastic effects in molecular thermoelectric transport.

Findings

Thermoelectric properties are dominated by quantum transport of virtual polarons.

Strong electron-phonon coupling significantly affects thermoelectric characteristics.

Asymmetry in electrode connection influences inelastic transport effects.

Abstract

Here we present a theoretical analysis of inelastic effects on 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 quantum transport of virtual polarons due to a strong electron-phonon coupling.