Inelastic effects in molecular junction transport: Scattering and self-consistent calculations for the Seebeck coefficient

TL;DR

This paper investigates how molecular vibrations affect the Seebeck coefficient in molecular junctions, comparing scattering theory and self-consistent Green's function methods, highlighting the importance of inelastic effects.

Contribution

It demonstrates the significance of inelastic effects on the Seebeck coefficient and compares two computational approaches, showing the limitations of scattering theory.

Findings

Inelastic effects significantly influence the Seebeck coefficient.

Scattering theory may fail to accurately predict inelastic effects.

Results align with recent experimental measurements.

Abstract

The influence of molecular vibration on the Seebeck coefficient is studied within a simple model. Results of a scattering theory approach are compared to those of a full self-consistent non-equilibrium Green's function scheme. We show, for a reasonable choice of parameters, that inelastic effects have non-negligible influence on the resulting Seebeck coefficient for the junction. We note that the scattering theory approach may fail both quantitatively and qualitatively. Results of calculation with reasonable parameters are in good agreement with recent measurements [P. Reddy et al., Science 315, 1568 (2007)]