Spin Relaxation in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>s</mml:mi></mml:math>-Wave Superconductors in the Presence of Resonant Spin-Flip Scatterers

Kochan, Denis; Barth, Michael; Costa, Andreas; Richter, Klaus; Fabian, Jaroslav

doi:10.1103/physrevlett.125.087001

Cited by 7 publications

(22 citation statements)

References 91 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, going beyond it one can depart from that conventional picture because of the appearances of bound states and resonances that shift spectral weights, or substantially renormalize the matrix elements entering the scattering rates. This has been shown in detail for the superconducting single layer graphene [37], where we have demonstrated the breakdown of the Hebel-Slichter effect due to the emergence of deep-in-gap immersed Yu-Shiba-Rusinov (YSR) states [50][51][52]. These findings are of general interest and they are valid beyond the specifics of graphene physics.…”

Section: Introductionsupporting

confidence: 59%

“…First, inspecting its energy poles within the superconducting gap gives the YSR bound state spectra [75]. Second, knowing the T-matrix one can directly access the spin-relaxation rate 1/τ s at a given chemical potential µ, temperature T , and the adatom concentration (per number of carbons) η ada , by evaluating the following ex-pression [37,42]:…”

Section: Green's Functions Spectral Properties and Theoretical Predic...mentioning

confidence: 99%

“…More precisely, we use the same implementation scheme as developed and described in details in Ref. [37] and its supplemental material. The starting point is to bring the model Hamiltonian, Eq.…”

Section: Numerical Implementation a Quasi-particle Spin Relaxation Ratesmentioning

confidence: 99%

“…Indeed, the proximity induced superconductivity in graphene has been experimentally demonstrated in lateral Josephson junctions [28][29][30][31], alkaline-intercalated graphite [32][33][34] and also vertical stacks with the interfacial geometries [35,36]. This becomes very promising from the point of view of superconducting spintronics based on graphene [37,38], where the interplay of electron spin with the superconducting coherence can serve as a knob for tuning graphene functionalities towards new applica-tions.…”

Section: Introductionmentioning

confidence: 99%

“…Here we go a step further and focus on BLG in a proximity of an s-wave superconductor, namely, on its quasi-particle spin properties that can be altered by the layer and sublattice degrees of freedom. Quite generally [37,41,42], spin relaxation in the s-wave superconductors manifests differently depending on whether the scattering is due to spin-orbit coupling (even w.r.t. time reversal) or magnetic exchange (odd w.r.t.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Spin relaxation, Josephson effect and Yu-Shiba-Rusinov states in superconducting bilayer graphene

Barth,

Fuchs,

Kochan

2021

Preprint

Self Cite

View full text Add to dashboard Cite

Bilayer graphene has two non-equivalent sublattices and, therefore, the same adatom impurity can manifest in spectrally distinct ways-sharp versus broad resonances near the charge neutralitydepending on the sublattice it adsorbs at. Employing Green's function analytical methods and the numerical Kwant package we investigate the spectral and transport interplay between the resonances and superconducting coherence induced in bilayer graphene by proximity to a s-wave superconductor. Analyzing doping and temperature dependencies of quasi-particle spin-relaxation rates, energies of Yu-Shiba-Rusinov states, Andreev spectra and the supercurrent characteristics of Josephson junctions we find unique superconducting signatures discriminating between resonant and off-resonant regimes. Our findings and predictions go in certain aspects beyond the specifics of the superconducting bilayer graphene and hold for generic s-wave superconductors functionalized by the resonant magnetic impurities.

show abstract

Section: Introductionsupporting

confidence: 59%

Section: Green's Functions Spectral Properties and Theoretical Predic...mentioning

confidence: 99%

Section: Numerical Implementation a Quasi-particle Spin Relaxation Ratesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Spin relaxation, Josephson effect and Yu-Shiba-Rusinov states in superconducting bilayer graphene

Barth,

Fuchs,

Kochan

2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

Spin relaxation and Yu-Shiba-Rusinov states in superconducting graphene

Kochan¹,

Barth²,

Costa³

et al. 2022

AIP Conference Proceedings

Self Cite

View full text Add to dashboard Cite

We study theoretically the relaxation of quasi-particle spins in graphene in proximity to an s-wave superconductor in the presence of resonant magnetic and spin-orbit active impurities. It is well known that off resonance, the relaxation behaves as predicted from superconducting coherence: with lower temperatures the spin relaxation increases when electrons scatter off magnetic impurities (Hebel-Slichter effect), and decreases when the scatterers act via spin-orbit coupling. This distinct temperature dependence, not available in the normal state, can uniquely discriminate between the two scattering mechanisms. We have shown [1] that the Hebel-Slichter picture breaks down when magnetic impurities act resonantly-the emergent Yu-Shiba-Rusinov states inside the gap shift the spectral weight of the magnetic resonances and thus suppress their interaction with quasi-particle states. As a consequence this leads to a significant decrease of the spin-relaxation rate at lower temperatures. Our findings are valid for generic s-wave superconductors that host resonant magnetic impurities.

show abstract

Signatures of superconducting triplet pairing in Ni–Ga-bilayer junctions

et al. 2022

Self Cite

View full text Add to dashboard Cite

Ni--Ga bilayers are a versatile platform for exploring the competition between strongly antagonistic ferromagnetic and superconducting phases. We characterize the impact of this competition on the transport properties of highly-ballistic Al/Al2O3(/EuS)/Ni--Ga tunnel junctions from both experimental and theoretical points of view. While the conductance spectra of junctions comprising Ni (3 nm)--Ga (60 nm) bilayers can be well understood within the framework of earlier results, which associate the emerging main conductance maxima with the junction films' superconducting gaps, thinner Ni (1.6 nm)--Ga (30 nm) bilayers entail completely different physics, and give rise to novel large-bias (when compared to the superconducting gap of the thin Al film as a reference) conductance-peak subseries that we term conductance shoulders. These conductance shoulders might attract considerable attention also in similar magnetic superconducting bilayer junctions, as we predict them to offer an experimentally well-accessible transport signature of superconducting triplet pairings that are induced around the interface of the Ni--Ga bilayer. We further substantiate this claim performing complementary polarized neutron reflectometry measurements on the bilayers, from which we deduce (1) a nonuniform magnetization structure in Ga in a several nanometer-thick area around the Ni--Ga boundary and can simultaneously (2) satisfactorily fit the obtained data only considering the paramagnetic Meissner response scenario. While the latter provides independent experimental evidence of induced triplet superconductivity inside the Ni--Ga bilayer, the former might serve as the first experimental hint of its potential microscopic physical origin. Finally, we introduce a simple phenomenological toy model to confirm also from the theoretical standpoint that superconducting triplet pairings around the Ni--Ga interface can indeed lead to the experimentally observed conductance shoulders, which convinces that our claims are robust and physically justified. Arranging our work in a broader context, we expect that Ni--Ga-bilayer junctions could have a strong potential for future superconducting-spintronics applications whenever an efficient engineering of triplet-pairing superconductivity is required.

show abstract

Spin Relaxation ins-Wave Superconductors in the Presence of Resonant Spin-Flip Scatterers

Cited by 7 publications

References 91 publications

Spin relaxation, Josephson effect and Yu-Shiba-Rusinov states in superconducting bilayer graphene

Spin relaxation, Josephson effect and Yu-Shiba-Rusinov states in superconducting bilayer graphene

Spin relaxation and Yu-Shiba-Rusinov states in superconducting graphene

Signatures of superconducting triplet pairing in Ni–Ga-bilayer junctions

Contact Info

Product

Resources

About