Influence of electron scatterings on thermoelectric effect

TL;DR

This study uses non-equilibrium Green's function methods to analyze how different electron scattering mechanisms influence the thermoelectric properties of nanowires, revealing conditions that optimize power factor enhancement.

Contribution

It introduces a detailed analysis of electron scattering effects on thermoelectric performance using B"uttiker probe modeling, highlighting optimal scattering conditions for power factor improvement.

Findings

Weak scattering increases conductance and power factor.

Strong scattering reduces conductance but slightly increases Seebeck coefficient.

Optimal scattering strength enhances power factor by 6-18%.

Abstract

In this work, we employed non-equilibrium Green's function to investigate the electron transport properties in the nanowire with the presence of scatterings. The scattering mechanism is modelled by using the concept of B\"uttiker probe. The effect of electron scattering is analyzed under three conditions: absence of external field; with a bias voltage; and with a finite temperature difference. It is found weak and strong scatterings strength affect the electron transport in different ways. In the case of weak scattering strength, electron trapping increase the electron density, hereafter boost the conductance significantly. Although the increment in conductance would reduce the Seebeck coefficient slightly, the power factor still increases. In the case of strong scattering strength, electron diffraction causes the redistribution of electrons, accumulation of electron at the ends of the wire blocks current flow; hence the conductance is reduced significantly. Although the Seebeck coefficient increases slightly, the power factor still decreases. The power factor is enhanced by 6%-18%, at the optimum scattering strength.