Thermal control across a chain of electronic nanocavities

We study a chain of alternating hot and cold electronic nanocavities--connected to one another via resonant-tunneling quantum dots--with the intent of achieving precise thermal control across the chain. This is accomplished by positioning the dots' energy levels such that a predetermined distribution of heat currents is realized across the chain in the steady state. The number of electrons in each cavity is conserved in the steady state which constrains the cavities' chemical potentials. We determine these chemical potentials analytically in the linear response regime where the energy differences between the dots' resonant levels and the neighboring chemical potentials are much smaller than the thermal energy. In this regime, the thermal control problem can be solved exactly, while, in the general case, thermal control can only be achieved in a relative sense, that is, when one only preassigns the ratios between different heat currents. We apply our results to two different cases: We first demonstrate that a "heat switch" can be easily realized with three coupled cavities, and then we show that our linear response results can provide accurate results in situations with a large number of cavities.