Thermoelectric properties of finite two-dimensional quantum dot arrays with band-like electronic states

TL;DR

This paper theoretically explores thermoelectric properties of 2D quantum dot arrays, revealing conditions where electron conductance and Seebeck coefficient can be optimized simultaneously, challenging traditional trade-offs.

Contribution

It demonstrates that in 2D quantum dot arrays, electron transport regimes allow simultaneous enhancement of conductance and Seebeck coefficient, offering new pathways for thermoelectric optimization.

Findings

Lorenz number satisfies Wiedemann-Franz law, confirming miniband formation.

In TATP, $G_e$ and $S$ can be enhanced together.

Increasing electronic states boosts $G_e$ without suppressing $S$.

Abstract

The thermal power ($PF=S^2G_e$) depends on the Seebeck coefficient ($S$) and electron conductance ($G_e$). The enhancement of $G_e$ will unavoidably suppress $S$ because they are closely related. As a consequence, the optimization of $PF$ is extremely difficult. Here, we theoretically investigated the thermoelectric properties of two-dimensional quantum dot (QD) arrays with carriers injected from electrodes. The Lorenz number of 2D QD arrays in the resonant tunneling procedure satisfies the Wiedemann-Franz law, which confirms the formation of minibands. When the miniband center is far away from the Fermi level of the electrodes, the electron transport is in the thermionic-assisted tunneling procedure (TATP). In this regime, $G_e$ in band-like situation and $S$ in atom-like situation can happen simultaneously. We have demonstrated that the enhancement of $G_e$ with an increasing number of electronic states will not suppress $S$ in the TATP.