Stimulated quasiparticles in spin-split superconductors

Virtanen, Pauli; Heikkilä, Tero T.; Bergeret, F. S.

doi:10.1103/physrevb.93.014512

Cited by 16 publications

(32 citation statements)

References 39 publications

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“…Thus, competing mechanisms are in play and a clear winner may not be ascertained a priori. Earlier works have investigated the influence of spinflip on the critical current [20] and critical temperature [20,21], the spatial and energy dependences of the DOS [22][23][24][25], the anomalous Green's function [26], and quasiparticles distribution [27,28] in a spin-split S.…”

Section: Introductionmentioning

confidence: 99%

Spin-flip enhanced thermoelectricity in superconductor-ferromagnet bilayers

et al. 2018

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We study the effects of spin-splitting and spin-flip scattering in a superconductor (S) on the thermoelectric (TE) properties of a tunneling contact to a metallic ferromagnet (F) using the Green's function method. A giant thermopower has been theoretically predicted and experimentally observed in such structures. This is attributed to the spin-dependent particle-hole asymmetry in the tunneling density of states (DOS) in the S/F heterostructure. Here, we evaluate the S DOS and thermopower for a range of temperatures, Zeeman-splitting, and spin-flip scattering. In contrast to the naive expectation based on the negative effect of spin-flip scattering on Cooper pairing, we find that the spin-flip scattering strongly enhances the TE performance of the system in the low-field and lowtemperature regime. This is attributed to a complex interplay between the charge and spin conductances caused by the softening of the spin-dependent superconducting gaps. The maximal value of the thermopower exceeds k B /e by a factor of ≈5 and has a non-monotonic dependence on spin-splitting and spin-flip rate.

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Section: Introductionmentioning

confidence: 99%

Spin-flip enhanced thermoelectricity in superconductor-ferromagnet bilayers

et al. 2018

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“…In other words, the quasiparticles should first equilibrate between themselves. (ii) In the presence of a spin-splitting field, also spin imbalance affects the quasiparticle-phonon heat flow [122,123]. Neglecting it therefore requires that the spin relaxation rate exceeds the injection rate causing the out-of-equilibrium situation.…”

Section: Electron-phonon Couplingmentioning

confidence: 99%

“…Spin accumulation and transport in superconductors has been considered in a number of theory papers [182,118,179,183,180,35,123,37,36,181]. Here we follow the approach developed in [35] that enables the description of all non-equilibrium modes, the effect of the spin-splitting field, and the various relaxation mechanisms.…”

Section: Nonequilibrium Properties Of a Superconductor With Spin Splimentioning

confidence: 99%

Thermal, electric and spin transport in superconductor/ferromagnetic-insulator structures

Heikkilä

Силаев

Virtanen

et al. 2019

Progress in Surface Science

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A ferromagnetic insulator (FI) attached to a conventional superconductor (S) changes drastically the properties of the latter. Specifically, the exchange field at the FI/S interface leads to a splitting of the superconducting density of states. If S is a superconducting film, thinner than the superconducting coherence length, the modification of the density of states occurs over the whole sample. The coexistence of the exchange splitting and superconducting correlations in S/FI structures leads to striking transport phenomena that are of interest for applications in thermoelectricity, superconducting spintronics and radiation sensors. Here we review the most recent progress in understanding the transport properties of FI/S structures by presenting a complete theoretical framework based on the quasiclassical kinetic equations. We discuss the coupling between the electronic degrees of freedom, charge, spin and energy, under non-equilibrium conditions and its manifestation in thermoelectricity and spin-dependent transport.

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“…It is inevitably accompanied by electric currents or voltages, that is, it leads to coupling charge, spin and heat degrees of freedom simultaneously. Another way is photoassisted spin imbalance 24 . But in this case the spin imbalance generation mechanism is strongly different.…”

Section: Introductionmentioning

confidence: 99%

Thermospin effects in superconducting heterostructures

Bobkova

Bobkov

2017

Phys. Rev. B

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Recently thermally created pure spin currents were predicted for Zeeman-split superconductor/normal metal heterostructures. Here it is shown that this "thermospin" current can lead to an accumulation of a pure spin imbalance in a system. The thermally induced spin imbalance can reach the value of Zeeman splitting of the superconducting DOS and strongly influences superconductivity in the heterostructure. Depending on the temperature difference between the superconductor and the normal reservoir it can enhance the critical temperature of the superconductor or additionally suppress the zero-temperature superconducting state. The last possibility gives rise to an unusual superconducting state, which starts to develop at finite temperature.

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Stimulated quasiparticles in spin-split superconductors

Cited by 16 publications

References 39 publications

Spin-flip enhanced thermoelectricity in superconductor-ferromagnet bilayers

Spin-flip enhanced thermoelectricity in superconductor-ferromagnet bilayers

Thermal, electric and spin transport in superconductor/ferromagnetic-insulator structures

Thermospin effects in superconducting heterostructures

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