Universal curve of optimum thermoelectric figures of merit for bulk and low-dimensional semiconductors

TL;DR

This paper derives analytical formulas linking thermoelectric figures of merit and power factors, revealing a universal curve that unifies bulk and low-dimensional semiconductors' thermoelectric performance.

Contribution

It introduces a universal curve connecting optimum thermoelectric figures of merit and power factors across different semiconductor dimensionalities.

Findings

Universal relationship between figures of merit and power factors.

Unified description for bulk and low-dimensional semiconductors.

Analytical formulas based on the one-band model.

Abstract

Analytical formulas for thermoelectric figure of merit and power factor are derived based on the one-band model. We find that there is a direct relationship between the optimum figures of merit and the optimum power factors of semiconductors despite of the fact that the two quantities are generally given by different values of chemical potentials. By introducing a dimensionless parameter consisting of optimum power factor and lattice thermal conductivity (without electronic thermal conductivity), it is possible to unify optimum figures of merit of both bulk and low-dimensional semiconductors into a single universal curve that covers lots of materials with different dimensionalities.