A Single-Quantum-Dot Heat Valve.

In the emerging field of quantum thermodynamics, heat transport and dissipation in a quantum electronic device is a fundamentally important topic. Gate-tunable single-quantum dot junctions are paradigmatic test benches for quantum transport. Whereas the study of charge transport therein has already allowed exploring a large palette of physical effects at play, heat transport and thermoelectric properties have only very recently started to be explored. Here, we demonstrate gate control of electronic heat flow in a single-quantum-dot junction. Electron temperature maps, as a function of the gate and bias voltages applied to the junction, reveal clearly defined Coulomb diamond structures with a maximum cooling right at the degeneracy point. This heat valve features a non-trivial bias and gate dependence revealing both the quantum nature of the dot at the heart of device and its strong coupling to leads.