Quantum Confinement Suppressing Electronic Heat Flow below the Wiedemann-Franz Law

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 a 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.

Automated summary

The Wiedemann-Franz law states that charge conductance and the electronic contribution to heat conductance are proportional. However, our experiments show that the heat conduction can be significantly lower than the predicted value due to quantum confinement and energy-selective transport properties in a semiconductor nanostructure. This opens up new possibilities for independently tailoring the thermal and electrical conduction properties.