Heat switch and thermoelectric effects based on Cooper-pair splitting and elastic cotunneling

Kirsanov, N. S.; Tan, Zhongchao; Golubev, Dmitry S.; Hakonen, Pertti; Lesovik, G. B.

doi:10.1103/physrevb.99.115127

Cited by 33 publications

(27 citation statements)

References 60 publications

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“…Cooper pairs from a superconductor (S) placed in the vicinity of a ferromagnet (F) may diffuse into the latter, thus modifying their electronic properties [1][2][3][4][5]. The engineering of this proximity effect in hybrid structures generated over the past few years considerable interest in thermoelectricity [6][7][8][9][10][11][12][13][14][15][16], spin caloric transport [17,18], and topological superconductivity [19][20][21][22][23][24]. Somewhat unexpected is that not only can ferromagnets [25][26][27][28] and antiferromagnetic insulators [29] cause spin imbalances into superconductors, but also normal metals [30] exploiting a superconductor itself may serve as a spin filter [31].…”

Section: Introductionmentioning

confidence: 99%

Phase-controlled spin and charge currents in a superconductor-ferromagnet hybrid

Rezaei

Hussein

Kamra

et al. 2020

Phys. Rev. Research

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We investigate spin-dependent quasiparticle and Cooper-pair transport through a central node interfaced with two superconductors and two ferromagnets. We demonstrate that voltage biasing of the ferromagnetic contacts induces superconducting triplet correlations on the node and reverses the supercurrent flowing between the two superconducting contacts. We further predict that such triplet correlations can mediate a tunable spin current flow into the ferromagnetic contacts. Our key finding is that noncollinearity in combination with spin-mixing results in equal-spin-triplet correlations on the node and leads to a net charge current between the unbiased two magnets. Our proposed device thus enables the generation, control, and detection of the typically elusive equal-spin-triplet Cooper pairs.

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Section: Introductionmentioning

confidence: 99%

Phase-controlled spin and charge currents in a superconductor-ferromagnet hybrid

Rezaei

Hussein

Kamra

et al. 2020

Phys. Rev. Research

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“…Note added.-Upon the completion of this work, we became aware of related works by R. Hussein et al 55 , and by N. S. Kirsanov et al 56 .…”

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confidence: 96%

Cooling by Cooper pair splitting

2018

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The electrons forming a Cooper pair in a superconductor can be spatially separated preserving their spin entanglement by means of quantum dots coupled to both the superconductor and independent normal leads. We investigate the thermoelectric properties of such a Cooper pair splitter and demonstrate that cooling of a reservoir is an indication of non-local correlations induced by the entangled electron pairs. Moreover, we show that the device can be operated as a non-local thermoelectric heat engine. Both as a refrigerator and as a heat engine, the Cooper pair splitter reaches efficiencies close to the thermodynamic bounds. As such, our work introduces an experimentally accessible heat engine and a refrigerator driven by entangled electron pairs in which the role of quantum correlations can be tested.Introduction.-Hybrid nanostructures with superconducting or normal electrodes connected by quantum wires provide a unique playground to test the interplay between transport and electron correlations 1 . Among these types of devices, Cooper pair splitters have received special attention due to their potential use as a source of non-locally entangled electron pairs 2-4 . A typical device consists of a central superconducting lead coupled to two normal ones through quantum dots, a geometry which has been successfully implemented using semiconducting nanowires 5-8 , carbon nanotubes 9,10 or graphene 11 . In this setup the Coulomb repulsion in the quantum dots forces the incoming electron pairs from the superconductor to separate into different normal electrodes, while local Andreev processes in which the two electrons from the pair are transferred to the same normal lead are strongly suppressed 2 . The Cooper pair splitting (CPS) process can be viewed as the time reverse of a crossed Andreev reflection in which an incoming electron from a given normal lead is reflected as a hole in the opposite lead 12,13 . Positive correlation between the currents through the two normal contacts has been presented as a signature of the splitting process 5,9,10 .

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“…M esoscopic thermoelectric effects have been investigated in a variety of condensed matter systems that, besides fundamental normal metal-superconductor-normal metal (NSN) systems [1][2][3][4][5] , also include quantum dots [6][7][8][9][10] , atomic point contacts [11][12][13] , Andreev interferometers 14,15 , superconducting rings 16 and nanowire heat engines 17 . Thermoelectric effects in the superconducting systems [18][19][20][21][22] , in particular those dealing with non-local thermoelectric currents in superconductor-ferromagnet devices [23][24][25] and in bulk nonmagnetic hybrid NSN structures [26][27][28] have attracted special attention.…”

mentioning

confidence: 99%

“…29 , established a mechanism for the coherent non-local thermoelectric effect in hybrid superconducting systems. This connection was further studied and explicitly described for a ballistic NSN structure 4 . It was revealed analytically in ref.…”

mentioning

confidence: 99%

Thermoelectric current in a graphene Cooper pair splitter

et al. 2021

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Generation of electric voltage in a conductor by applying a temperature gradient is a fundamental phenomenon called the Seebeck effect. This effect and its inverse is widely exploited in diverse applications ranging from thermoelectric power generators to temperature sensing. Recently, a possibility of thermoelectricity arising from the interplay of the non-local Cooper pair splitting and the elastic co-tunneling in the hybrid normal metal-superconductor-normal metal structures was predicted. Here, we report the observation of the non-local Seebeck effect in a graphene-based Cooper pair splitting device comprising two quantum dots connected to an aluminum superconductor and present a theoretical description of this phenomenon. The observed non-local Seebeck effect offers an efficient tool for producing entangled electrons.

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Heat switch and thermoelectric effects based on Cooper-pair splitting and elastic cotunneling

Cited by 33 publications

References 60 publications

Phase-controlled spin and charge currents in a superconductor-ferromagnet hybrid

Phase-controlled spin and charge currents in a superconductor-ferromagnet hybrid

Cooling by Cooper pair splitting

Thermoelectric current in a graphene Cooper pair splitter

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