Quantum confinement suppressing electronic heat flow below the Wiedemann-Franz law

TL;DR

This study demonstrates that quantum confinement in a semiconductor quantum dot can significantly suppress electronic heat flow below the Wiedemann-Franz law, enabling independent control of heat and charge conduction.

Contribution

The paper provides experimental evidence that quantum confinement in a quantum dot can reduce electronic heat conductance below the Wiedemann-Franz law, offering new ways to tailor thermoelectric properties.

Findings

Heat conduction below Wiedemann-Franz law achieved

Quantum confinement causes energy-selective transport

Potential for independent control of heat and charge flow

Abstract

The Wiedemann-Franz law states that the charge conductance and the electronic contribution to the heat conductance are proportional. This sets stringent constraints on efficiency bounds for thermoelectric applications, which seek for large charge conduction in response to a small heat flow. We present experiments based on a quantum dot formed inside a semiconducting InAs nanowire transistor, in which the heat conduction can be tuned significantly below the Wiedemann-Franz prediction. Comparison with scattering theory shows that this is caused by quantum confinement and the resulting energy-selective transport properties of the quantum dot. Our results open up perspectives for tailoring independently the heat and electrical conduction properties in semiconductor nanostructures.