A three-terminal heat engine based on resonant-tunneling multi-level quantum dots

A three-terminal heat engine based on resonant-tunneling multi-level quantum dots is proposed. With the help of Landauer formula, the general expressions for the charge and heat currents, the power output and efficiency are derived. In the linear response regime an explicit analytic expressions for the charge and heat currents, the maximum power output and the corresponding efficiency is presented. Next, the performance characteristic and optimal performance of the heat engine is investigated in the nonlinear response regime by numerical calculation. Finally, the influence of the main parameters, including the asymmetry factor, the energy-level spacing, the energy difference, the number of discrete energy levels, the bias voltage, and the temperature difference on the optimal performance of the heat engine is analyzed in detail. By choosing appropriate parameters one can obtain the maximum power output and the corresponding efficiency at maximum output power. Graphical abstract A Schematic diagram of a three-terminal heat engine with resonant-tunneling multi-level quantum dots. A central cavity (red) with chemical potential C is connected μc to the left/right electron reservoir (blue) via multi-level quantum dots. The direction of the arrow indicates the positive direction of the current and heat flow. B The optimized power output Popt in units of $$\frac{{({k_B}T)^2}}{{2\hbar}}$$ ( k B T ) 2 2 ħ and the corresponding efficiency ηP in unit of ηC as a function of N for given $$\delta E=0.1k_{B}T$$ δ E = 0.1 k B T . C The optimized power output Popt and the corresponding efficiency ηP as a function of $$\delta E$$ δ E for given N = 11. D The maximum power output Pmax in units of $$\frac{{({k_B}T)^2}}{{2\hbar}}$$ ( k B T ) 2 2 ħ and the corresponding efficiency ηP in units of ηC as a function of the temperature difference $$\Delta / T$$ Δ / T