scholarly journals Coexistence and tuning of spin-singlet and triplet transport in spin-filter Josephson junctions

2022 ◽  
Vol 5 (1) ◽  
Author(s):  
Halima Giovanna Ahmad ◽  
Martina Minutillo ◽  
Roberto Capecelatro ◽  
Avradeep Pal ◽  
Roberta Caruso ◽  
...  
Keyword(s):  
Josephson Junctions ◽  
Josephson Effect ◽  
Theoretical Modelling ◽  
A Posteriori ◽  
Spin Filter ◽  
Spin Singlet ◽  
Spin Polarized ◽  
Triplet Correlation ◽  
Inhomogeneous Superconductor ◽  
Direct Correspondence

AbstractThe increased capabilities of coupling more and more materials through functional interfaces are paving the way to a series of exciting experiments and extremely advanced devices. Here we focus on the capability of magnetically inhomogeneous superconductor/ferromagnet (S/F) interfaces to generate spin-polarized triplet pairs. We build on previous achievements on spin-filter ferromagnetic Josephson junctions (JJs) and find direct correspondence between neat experimental benchmarks in the temperature behavior of the critical current and theoretical modelling based on microscopic calculations, which allow to determine a posteriori spin-singlet and triplet correlation functions. This kind of combined analysis provides an accurate proof of the coexistence and tunability of singlet and triplet transport. This turns to be a powerful way to model disorder and spin-mixing effects in a JJ to enlarge the space of parameters, which regulate the phenomenology of the Josephson effect and could be applied to a variety of hybrid JJs.

scholarly journals Anomalous anisotropic behaviour of spin-triplet proximity effect in Au/SrRuO3/Sr2RuO4 junctions

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
M. S. Anwar ◽  
M. Kunieda ◽  
R. Ishiguro ◽  
S. R. Lee ◽  
C. Sow ◽  
...  
Keyword(s):  
Proximity Effect ◽  
Magnetic Inhomogeneity ◽  
Anisotropic Behaviour ◽  
Electronic Spin ◽  
Anisotropic Field ◽  
Spin Singlet ◽  
Spin Polarized ◽  
Field Response ◽  
Spin Triplet ◽  
Triplet Correlation

Abstract Spin-polarized supercurrents can be generated with magnetic inhomogeneity at a ferromagnet/spin-singlet-superconductor interface. In such systems, complex magnetic inhomogeneity makes it difficult to functionalise the spin-polarized supercurrents. However, spin-polarized supercurrents in ferromagnet/spin-triplet-superconductor junctions can be controlled by the angle between magnetization and spin of Copper pairs (d-vector), that can effectively be utilized in developing of a field of research known as superconducting spintronics. Recently, we found induction of spin-triplet correlation into a ferromagnet SrRuO3 epitaxially deposited on a spin-triplet superconductor Sr2RuO4, without any electronic spin-flip scattering. Here, we present systematic magnetic field dependence of the proximity effect in Au/SrRuO3/Sr2RuO4 junctions. It is found that induced triplet correlations exhibit strongly anisotropic field response. Such behaviour is attributed to the rotation of the d-vector of Sr2RuO4. This anisotropic behaviour is in contrast with the vortex dynamic. Our results will stimulate study of interaction between ferromagnetism and unconventional superconductivity.

scholarly journals Josephson effect in junctions of conventional and topological superconductors

2018 ◽  
Vol 9 ◽  
pp. 1659-1676 ◽  
Author(s):  
Alex Zazunov ◽  
Albert Iks ◽  
Miguel Alvarado ◽  
Alfredo Levy Yeyati ◽  
Reinhold Egger
Keyword(s):  
Bound States ◽  
Josephson Effect ◽  
Mean Field ◽  
Josephson Current ◽  
Field Analysis ◽  
Current Phase ◽  
Topological Superconductor ◽  
Topological Superconductors ◽  
Spin Singlet ◽  
Hybrid Devices

We present a theoretical analysis of the equilibrium Josephson current-phase relation in hybrid devices made of conventional s-wave spin-singlet superconductors (S) and topological superconductor (TS) wires featuring Majorana end states. Using Green’s function techniques, the topological superconductor is alternatively described by the low-energy continuum limit of a Kitaev chain or by a more microscopic spinful nanowire model. We show that for the simplest S–TS tunnel junction, only the s-wave pairing correlations in a spinful TS nanowire model can generate a Josephson effect. The critical current is much smaller in the topological regime and exhibits a kink-like dependence on the Zeeman field along the wire. When a correlated quantum dot (QD) in the magnetic regime is present in the junction region, however, the Josephson current becomes finite also in the deep topological phase as shown for the cotunneling regime and by a mean-field analysis. Remarkably, we find that the S–QD–TS setup can support φ0-junction behavior, where a finite supercurrent flows at vanishing phase difference. Finally, we also address a multi-terminal S–TS–S geometry, where the TS wire acts as tunable parity switch on the Andreev bound states in a superconducting atomic contact.

SPIN STRUCTURES IN INHOMOGENEOUS FRACTIONAL QUANTUM HALL SYSTEMS

2004 ◽  
Vol 18 (27n29) ◽  
pp. 3871-3874 ◽  
Author(s):  
KAREL VÝBORNÝ ◽  
DANIELA PFANNKUCHE
Keyword(s):  
Ground State ◽  
Quantum Hall ◽  
Exact Diagonalization ◽  
Fractional Quantum ◽  
Fractional Quantum Hall ◽  
Spin Structures ◽  
Quantum Hall Systems ◽  
Magnetic Inhomogeneities ◽  
Spin Singlet ◽  
Spin Polarized

Transitions between spin polarized and spin singlet incompressible ground state of quantum Hall systems at filling factor 2/3 are studied by means of exact diagonalization with eight electrons. We observe a stable exactly half–polarized state becoming the absolute ground state around the transition point. This might be a candidate for the anomaly observed during the transition in optical experiments. The state reacts strongly to magnetic inhomogeneities but it prefers stripe–like spin structures to formation of domains.

Josephson Effect in SFNS Josephson Junctions

2011 ◽  
pp. 171-218 ◽  
Author(s):  
T. Yu. Karminskaya ◽  
M. Yu. Kupriyanov ◽  
A. A. Golubov ◽  
A. S. Sidorenko
Keyword(s):  
Josephson Junctions ◽  
Josephson Effect

scholarly journals Author Correction: Joule overheating poisons the fractional ac Josephson effect in topological Josephson junctions

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Kévin Le Calvez ◽  
Louis Veyrat ◽  
Frédéric Gay ◽  
Philippe Plaindoux ◽  
Clemens B. Winkelmann ◽  
...  
Keyword(s):  
Josephson Junctions ◽  
Josephson Effect

scholarly journals Spin Polarized Current Injection Through ${\rm HgBr}_{2}$ Intercalated Bi2212 Intrinsic Josephson Junctions

2007 ◽  
Vol 17 (2) ◽  
pp. 577-580 ◽  
Author(s):  
L.. Ozyuzer ◽  
C.. Kurter ◽  
M.. Ozdemir ◽  
J.F. Zasadzinski ◽  
K.E. Gray ◽  
...  
Keyword(s):  
Josephson Junctions ◽  
Current Injection ◽  
Intrinsic Josephson Junctions ◽  
Spin Polarized

Perfect spin-filter devices based on zigzag zinc oxide nanoribbons

2016 ◽  
Vol 30 (32n33) ◽  
pp. 1650392 ◽  
Author(s):  
Zi-Yue Zhang
Keyword(s):  
Zinc Oxide ◽  
Electron Transport ◽  
Spin Polarization ◽  
Bias Voltage ◽  
First Principles ◽  
External Fields ◽  
Spin Filter ◽  
Spin Polarized ◽  
Spin Filters ◽  
Filtering Effect

Spin-polarized electron transport through a zigzag zinc oxide nanoribbon (ZnONR) has been studied using first-principles transport simulations. Ribbons without edges passivated show 100% spin polarization at small bias voltage independently of width. The ribbons with edge zinc atoms passivated maintain absolute spin-filtering effect in much larger bias region. The results demonstrate that zigzag ZnONRs act as perfect spin-filters in the absence of magnetic electrodes and external fields.

SPIN DEPENDENCE OF PAIR TUNNELING PROPERTIES OF Bi2Sr2CaCu2O8+x INTRINSIC JOSEPHSON JUNCTIONS

2005 ◽  
Vol 19 (01n03) ◽  
pp. 199-203 ◽  
Author(s):  
DO BANG ◽  
HU-JONG LEE ◽  
MYUNG-HO BAE ◽  
WANG-HYUN PARK
Keyword(s):  
External Field ◽  
Single Crystal ◽  
Josephson Junctions ◽  
Phase Fluctuation ◽  
Superconducting Gap ◽  
Spin Dependence ◽  
Intrinsic Josephson Junctions ◽  
Pair Tunneling ◽  
Spin Polarized ◽  
Pancake Vortices

Detailed tunneling characteristics of a stack of intrinsic Josephson junctions in a Bi 2 Sr 2 CaCu 2 O 8+x single crystal were obtained both in spin-degenerate and spin-polarized bias configurations. Injection of the spin-polarized quasiparticles effectively weakened the in-plane superconducting strength and the interlayer Jospehson coupling. The superconducting gap and the Josephson critical current of the stack were, in general, further suppressed by an external field applied in parallel with the c-axis direction. Study of the spin-dependent tunneling characteristics may provide valuable information on clarifying the mechanism of high-Tc superconductivity as well as the interlayer phase fluctuation induced by the "pancake vortices" on CuO 2 layers.

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