Nonlocal thermoelectric effects in high-field superconductor-ferromagnet hybrid structures

Heidrich, Jonas; Beckmann, D.

doi:10.1103/physrevb.100.134501

Cited by 20 publications

(19 citation statements)

References 28 publications

(46 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Coupled charge and spin transport, or spintronics, emerged in the late 1980s 2 . Later, spin caloritronics or coupled heat, charge and spin transport 3,4 became an experimental reality with the observation of the spin Seebeck effect 5 and spin-dependent Peltier effects 6 in normal metals, and very recently large spin-dependent thermoelectric effects in superconductor-based devices [7][8][9][10][11] .…”

mentioning

confidence: 99%

Evidence for spin-dependent energy transport in a superconductor

Kuzmanović¹,

Wu²,

Weideneder³

et al. 2020

Nat Commun

View full text Add to dashboard Cite

In ferromagnetic materials, spin up and down electrons can carry different heat currents. This spin-dependent energy excitation mode ('spin energy mode') occurs only when spin up and down energy distribution functions are different. In superconductors, heat is carried by quasiparticle excitations and the spin energy mode can be excited by spin-polarised current injection. In the presence of a finite Zeeman magnetic field, the spin energy mode surprisingly leads to a charge imbalance (different numbers of hole-and electron-like quasiparticles) at the superconducting gap edge. By performing spin-resolved spectroscopy of the out-ofequilibrium quasiparticle populations in a mescoscopic superconductor, we reveal that their distribution functions are non-Fermi-Dirac. In addition, our spectroscopic technique allows us to observe a charge imbalance, localised in energy to the gap edge and thus unambiguously identify the spin energy mode. Our results agree well with theory and shed light on energy transport in superconducting spintronics.

show abstract

mentioning

confidence: 99%

Evidence for spin-dependent energy transport in a superconductor

Kuzmanović¹,

Wu²,

Weideneder³

et al. 2020

Nat Commun

View full text Add to dashboard Cite

show abstract

“…With such parameters the charge current amplitude corresponding to Fig. 2 is ePI 0 = 20 nA, which is two orders of magnitude larger than the nonlocal thermoelectric current measured recently in a similar setup [47]. The maximal HM resonance frequency in Al is 2 = 100 GHz, which is within the capability of modern spectrum analysers.…”

Section: A Electrical Detection Of the Higgs Modementioning

confidence: 54%

“…The suggested effect of SHG charge current coupled to the HM can be measured, for example, in thin films of Al superconductor placed in a tunnel contact with FM iron electrodes similar to the setups used in the measurement of the nonlocal spin signals [38][39][40][43][44][45][46][47]. With T c = 1.6 K and gap 0 = 2 × 10 −4 eV, the spin-splitting field h = 0.2 0 can be obtained with an external in-plane magnetic field B ≈ 0.5 T, and the polarization of this type of FM contact [44] is P = 0.2.…”

Section: A Electrical Detection Of the Higgs Modementioning

confidence: 99%

“…Here we suggest a different mechanism allowing electrical detection of HMs due to their coupling with spin and charge degrees of freedom in high-field superconductor/ferromagnet junctions. Unusual transport properties of such systems have attracted intense attention [34][35][36][37], stimulating both experimental [38][39][40][41][42][43][44][45][46][47] and theoretical efforts [34,[48][49][50][51][52][53][54][55][56][57].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Spin and charge currents driven by the Higgs mode in high-field superconductors

Силаев

Ojajärvi

Heikkilä

2020

Phys. Rev. Research

View full text Add to dashboard Cite

The Higgs mode in superconducting materials describes slowly decaying oscillations of the order parameter amplitude. We demonstrate that in superconductors with a built-in spin-splitting field the Higgs mode is strongly coupled to the spin degrees of freedom, allowing for the generation of time-dependent spin currents. Converting such spin currents to electric signals by spin-filtering elements provides a tool for the second-harmonic generation and the electrical detection of the Higgs mode generated by the external irradiation. The nonadiabatic spin torques generated by these spin currents allow for the magnetic detection of the Higgs mode by measuring the precession of the magnetic moment in the adjacent ferromagnet. We discuss also the reciprocal effect, which is the generation of the Higgs mode by the magnetic precession. Coupling the collective modes in superconductors to light and magnetic dynamics provides an opportunity for the study of superconducting optospintronics.

show abstract

“…The requirement of large magnetic field was subsequently eliminated by using a ferromagnetic insulator a year later [45]. Very recently, nonlinear thermoelectric effects have also been experimentally observed in FM/SC structures [31,46].…”

Section: Introductionmentioning

confidence: 99%

Thermoelectricity carried by proximity-induced odd-frequency pairing in ferromagnet/superconductor junctions

2020

View full text Add to dashboard Cite

We explore the role of proximity-induced odd-frequency pairing in the thermoelectricity of a ferromagnet when coupled to a conventional s-wave spin-singlet superconductor through a spin-active interface. By varying both the polarization and its direction in the ferromagnet and the interfacial spin-orbit interaction strength, we analyze the behavior of all proximity-induced pair amplitudes in the ferromagnet and their contributions to the thermoelectric coefficients. Based on our results for the Seebeck coefficient, we predict that odd-frequency spin-triplet Cooper pairs are much more efficient than the conventional spin-singlet even-frequency pairs in enhancing thermoelectricity of the junction, and especially mixed-spin triplet pairing is favorable. Our results on the thermoelectric figure of merit show that ferromagnet/superconductor junctions are very good thermoelectric systems when superconductivity is dominated by odd-frequency pairing.

show abstract

Nonlocal thermoelectric effects in high-field superconductor-ferromagnet hybrid structures

Cited by 20 publications

References 28 publications

Evidence for spin-dependent energy transport in a superconductor

Evidence for spin-dependent energy transport in a superconductor

Spin and charge currents driven by the Higgs mode in high-field superconductors

Thermoelectricity carried by proximity-induced odd-frequency pairing in ferromagnet/superconductor junctions

Contact Info

Product

Resources

About