A triple-quantum-dot ring as a micro-cooler

The novel cycle model of a three-quantum-dot cooler, which possesses three Fermi reservoirs connected by three quantum dots to form a ring, is proposed. The roles of the properties of thermal reservoirs and the energy levels of quantum dots in determining the thermodynamic characteristics of the cooler are revealed. Quantitative analyses of the necessary conditions of cooling in the cases of particle flows moving clockwise or counterclockwise in the ring are obtained. The energy levels of quantum dots and the chemical potentials of heat reservoirs are selected optimally so that the cooler attains its maximum cooling rate. The effects of the chemical potentials of heat reservoirs on the systemic performance are analyzed. The optimal values of other parameters at the maximum cooling rate are calculated numerically, and the optimal selection criteria of main parameters are provided. All these results obtained here reveal a useful approach toward high-performance quantum refrigerators in multi-terminal nanoscale systems