We demonstrate that a far-field transistor made up of a phase-change material base with thermal hysteresis can efficiently be used as a thermal device capable of heating and cooling. Based on the principle of energy conservation for the heat currents by radiation, conduction, and convection, it is shown that the base temperature undergoes significant jumps as the transistor amplification factor is optimized. When the collector and emitter of the transistor operate at 350 and 300 K, respectively, a temperature jump of $+18\mathrm{K}$ ($-5\mathrm{K}$) is obtained during the heating (cooling) of a ${\mathrm{VO}}_2$ base excited with $208\mathrm{W}{\mathrm{m}}^{-2}$ ($63\mathrm{W}{\mathrm{m}}^{-2}$). These significant jumps are mainly driven by the photon heat current and could open new perspectives on thermal machines.

• Received 25 May 2016

DOI:https://doi.org/10.1103/PhysRevApplied.6.054003