Polarons in 2+epsilon dimensions and giant figure of merit of semiconducting nanolayers

TL;DR

This paper investigates how polaron confinement in semiconducting nanolayers influences their thermoelectric properties, revealing a significant enhancement in thermoelectric efficiency due to polaron effects in reduced dimensions.

Contribution

It provides a theoretical analysis of polaron energy spectrum and thermopower in confined systems, explaining experimental observations and proposing methods to improve thermoelectric performance.

Findings

Polaron mass enhancement explains giant thermoelectric power in nanolayers.

Confinement significantly alters polaron properties and transport.

Proposed enhancement of thermoelectric figure of merit by over an order of magnitude.

Abstract

Polarons - electrons coupled with lattice vibrations - play a key role in the transport and optical properties of many systems of reduced dimension and dimensionality. Their confinement affects drastically the phonon, polaron, bipolaron and multi-polaron properties of quantum wells. Here we calculate the energy spectrum and thermopower of polarons confined to a potential well as a function of the well thickness. We show that the polaron mass enhancement in 2+epsilon dimensions explains a giant thermolectric power recently observed in doped semiconducting nanolayers (multiple quantum wells (MQWs)), and propose a route for enhancing the performance of thermoelectric energy nanoconverters increasing their figure of merit by more than one order of magnitude.