Three-terminal heat engine and refrigerator based on superlattices

TL;DR

This paper introduces a three-terminal thermoelectric device based on semiconductor superlattices that achieves high power output and dual functionality as a heat engine and refrigerator, with analysis of phonon heat currents.

Contribution

It presents a novel superlattice-based thermoelectric device with enhanced power and dual operation modes, including detailed performance and phonon heat current analysis.

Findings

Power output nearly twice that of quantum well devices

Effective as both heat engine and refrigerator under different conditions

Phonon heat current can be reduced, especially at low temperatures

Abstract

We propose a three terminal heat engine based on semiconductor superlattices for energy harvesting. The periodicity of the superlattice structure creates an energy miniband, giving an energy window for allowed electron transport. We find that this device delivers a large power, nearly twice than the heat engine based on quantum wells, with a small reduction of efficiency. This engine also works as a refrigerator in a different regime of the system's parameters. The thermoelectric performance of the refrigerator is analyzed, including the cooling power and coefficient of performance in the optimized condition. We also calculate phonon heat current through the system, and explore the reduction of phonon heat current compared to the bulk material. The direct phonon heat current is negligible at low temperatures, but dominates over the electronic at room temperature and we discuss ways to reduce it.