Comparative study of heat-driven and power-driven refrigerators with Coulomb-coupled quantum dots

Abstract

Multiterminal multidot devices have been put forward as versatile and high-performing setups for thermoelectric energy harvesting at the nanoscale. With a technique that encompasses and overtakes several of the usual theoretical tools used in this context, we explore a three-terminal Coulomb-coupled-dot device for refrigeration purposes. The refrigerator is monitored by either a voltage or a thermal bias. This comparative study shows that the heat-driven refrigerator is underperforming relative to the power-driven one, due to scarce on-dot charge fluctuations.

Heat Modulation on Target Thermal Bath via Coherent Auxiliary Bath

“…These non-intuitive physical behaviors have become an apparent challenge to the standard laws of thermodynamics [ 15 , 16 ]. The rapid progress of quantum technologies has allowed us to characterize the quantum machine [ 17 , 18 , 19 , 20 ] and experimentally realized them in various quantum systems [ 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 ]. With the aid of these controllable quantum platforms (systems), some studies focus on the redefinitions of some concepts, such as work and heat [ 31 , 32 , 33 , 34 ], and the verification and modification of thermodynamics second law [ 35 ] in quantum domain.…”

A realistic non-local heat engine based on Coulomb coupled systems

“…As such, one of the crucial focus of the modern thermoelectric community is to facilitate an independent optimization of the electron transport path and lattice heat conduction path, by introducing a spatial separation between the current path and the heat reservoir [17][18][19]. This phenomenon of harvesting heat from a reservoir, which is spatially separated from the current conduction path, is known as non-local heat harvesting [1][2][3][4][5][17][18][19][20]. In this case, tailoring the lattice heat transport path, in an attempt to gain enhanced efficiency, can be accomplished without altering the current conduction path.…”

“…In this case, tailoring the lattice heat transport path, in an attempt to gain enhanced efficiency, can be accomplished without altering the current conduction path. Recently designs and concepts of non-local heat engines and refrigerators using Coulomb coupled quantum dots have been proposed and explored in literature [1][2][3][4][5]20]. However, the operation of such non-local heat engines demand a sharp step-like change in the system-to-reservoir coupling around the ground state energy [1][2][3][4][5]20], which is impossible to achieve in a practical scenario.…”

“…Recently designs and concepts of non-local heat engines and refrigerators using Coulomb coupled quantum dots have been proposed and explored in literature [1][2][3][4][5]20]. However, the operation of such non-local heat engines demand a sharp step-like change in the system-to-reservoir coupling around the ground state energy [1][2][3][4][5]20], which is impossible to achieve in a practical scenario. In this paper, I propose a realistic design strategy to accomplish non-local heat harvesting using capacitively coupled quantum dots.…”

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Optimal non-local heat-engines, based on Coulomb-coupled systems, demand a sharp step-like change in energy resolved system-to-reservoir coupling around the ground state of quantum-dots [1][2][3][4][5]. Such sharp step-like transition in the system-to-reservoir coupling cannot be achieved in a realistic scenario.

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