Heat sources in electronic refrigerators

Jug, B.; Trontelj, Z.

doi:10.1109/77.919477

Cited by 5 publications

(4 citation statements)

References 10 publications

(2 reference statements)

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“…Though the principle of operation is rather straightforward, the high cooling power requires high density of nonequilibrium quasiparticles injected into the superconductor and accumulated near the tunnel interface [42,96]. The consequences are the backtunneling of hot quasiparticles to the normal metal [96,102], the emission of phonons that partially penetrate the normal metal [42,102], and the overheating of the superconducting electrode [42]. All these effects reduce the efficiency of NIS refrigerators.…”

Section: Nonequilibrium Electron Coolingmentioning

confidence: 99%

Relaxation of nonequilibrium quasiparticles in mesoscopic size superconductors

Arutyunov

Chernyaev

Karabassov

et al. 2018

J. Phys.: Condens. Matter

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Rapid development of micro- and nanofabrication methods have provoked interest and enabled experimental studies of electronic properties of a vast class of (sub)micrometer-size solid state systems. Mesoscopic-size hybrid structures, containing superconducting elements, have become interesting objects for basic research studies and various applications, ranging from medical and astrophysical sensors to quantum computing. One of the most important aspects of physics, governing the behavior of such systems, is the finite concentration of nonequilibrium quasiparticles, present in a superconductor even well below the temperature of superconducting transition. Those nonequilibrium excitations might limit the performance of a variety of superconducting devices, like superconducting qubits, single-electron turnstiles and microrefrigerators. On the contrary, in some applications, like detectors of electromagnetic radiation, the nonequilibrium state is essential for their operation. It is therefore of vital importance to study the mechanisms of nonequilibrium quasiparticle relaxation in superconductors of mesoscopic dimensions, where the whole structure can be considered as an 'interface'. At early stages of research the problem was mostly studied in relatively massive systems and at high temperatures close to the critical temperature of a superconductor. We review the recent progress in studies of nonequilibrium quasiparticle relaxation in superconductors including the low temperature limit. We also discuss the open physical questions and perspectives of development in the field.

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Section: Nonequilibrium Electron Coolingmentioning

confidence: 99%

Relaxation of nonequilibrium quasiparticles in mesoscopic size superconductors

Arutyunov

Chernyaev

Karabassov

et al. 2018

J. Phys.: Condens. Matter

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“…Serious limitations of the cooling effect arise from the fact that nonequilibrium quasiparticles injected into the superconducting electrode accumulate near the tunnel interface. 7,8 The consequences are the backtunneling of hot quasiparticles to the normal metal 8,9 , the emission of phonons (by the recombination of nonequilibrium quasiparticles into Cooper pairs) that partially penetrate the normal metal, 7,9 and the overheating of the superconducting electrode. 7 All these effects reduce the efficiency of NIS refrigerators.…”

Section: Introductionmentioning

confidence: 99%

Electron cooling by diffusive normal metal–superconductor tunnel junctions

et al. 2010

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We investigate heat and charge transport in NN ′ IS tunnel junctions in the diffusive limit. Here N and S are massive normal and superconducting electrodes (reservoirs), N ′ is a normal metal strip, and I is an insulator. The flow of electric current in such structures at subgap bias is accompanied by heat transfer from the normal metal into the superconductor, which enables refrigeration of electrons in the normal metal. We show that the two-particle current due to Andreev reflection generates Joule heating, which is deposited in the N electrode and dominates over the single-particle cooling at low enough temperatures. This results in the existence of a limiting temperature for refrigeration. We consider different geometries of the contact: one-dimensional and planar, which is commonly used in the experiments. We also discuss the applicability of our results to a doublebarrier SINIS microcooler.

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“…[7][8][9] As a consequence hot quasiparticles may tunnel back into the normal metal, leading to a reduction of the cooling effect. 9,10 In order to overcome this problem a so called quasiparticle trap, 11 made of an additional normal metal layer has been attached to the superconducting electrode, removing hot quasiparticles from the superconductor. Recently, it was also shown that a small magnetic field enhances relaxation processes in a superconductor and leads to significant improvement of the cooling power in NIS junctions.…”

Section: Introductionmentioning

confidence: 99%

Electron cooling in diffusive normal metal - superconductor tunnel junctions with a spin-valve ferromagnetic interlayer

Ozaeta,

Vasenko,

Hekking

et al. 2012

Preprint

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We investigate heat and charge transport through a diffusive SIF 1 F 2 N tunnel junction, where N (S) is a normal (superconducting) electrode, I is an insulator layer and F 1,2 are two ferromagnets with arbitrary direction of magnetization. The flow of an electric current in such structures at subgap bias is accompanied by a heat transfer from the normal metal into the superconductor, which enables refrigeration of electrons in the normal metal. We demonstrate that the refrigeration efficiency depends on the strength of the ferromagnetic exchange field h and the angle α between the magnetizations of the two F layers. As expected, for values of h much larger than the superconducting order parameter ∆, the proximity effect is suppressed and the efficiency of refrigeration increases with respect to a NIS junction. However, for h ∼ ∆ the cooling power (i.e. the heat flow out of the normal metal reservoir) has a non-monotonic behavior as a function of h showing a minimum at h ≈ ∆. We also determine the dependence of the cooling power on the lengths of the ferromagnetic layers, the bias voltage, the temperature, the transmission of the tunneling barrier and the magnetization misalignment angle α.

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Heat sources in electronic refrigerators

Cited by 5 publications

References 10 publications

Relaxation of nonequilibrium quasiparticles in mesoscopic size superconductors

Relaxation of nonequilibrium quasiparticles in mesoscopic size superconductors

Electron cooling by diffusive normal metal–superconductor tunnel junctions

Electron cooling in diffusive normal metal - superconductor tunnel junctions with a spin-valve ferromagnetic interlayer

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