Tuning the 0 − π Josephson junction with a magnetic impurity: Role of tunnel contacts, exchange coupling, e − e interactions and high-spin states

Pal, Subhajit; Benjamin, Colin

doi:10.1038/s41598-018-23517-w

Cited by 9 publications

(9 citation statements)

References 32 publications

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“…] − E F . In the Hamiltonian "H 0 ", the first term describes the kinetic energy of an electron with mass m , the second term depicts interfaces-V is the strength of the δ-like potential at the interfaces between ferromagnet and superconductor, the third term describes magnetic impurity with J 0 being the strength of exchange interaction between the electron with spin s and the magnetic impurity with spin S [21,22], the fourth term describes ferromagnet's with h being the magnetization vectors of the two ferromagnet's and Θ is the Heaviside step function. Further, ψ(x) is a four-component spinor, E F is the Fermi energy,σ is the Pauli spin matrix andÎ is the 2 × 2 identity matrix.…”

Section: A Hamiltonianmentioning

confidence: 99%

“…1), we will get the wavefunctions for left and right superconductors. The wave function in the left superconductor (for x < − a 2 ) is [21,24]-…”

Section: Wave-functionsmentioning

confidence: 99%

“…If we solve the Bogoliubov-de Gennes equation for superconductors (see equation (2.1)), we will get the wave functions for left and right superconductors. The wave function in the left superconductor (for x < −a/2) is [21,24]-…”

Section: (I) Wave Functionsmentioning

confidence: 99%

“…The boundary conditions can be written as follows [21,24]: at x = −a/2-ψ S L (x) = ψ F 1 (x) (continuity of wave functions) and (dψ…”

Section: (Ii) Boundary Conditionsmentioning

confidence: 99%

“…The aforesaid method of addressing spin-flip scattering process is not unique to our work, many other papers have used the same model of spin-flip scattering in different context, mention may be made of the first paper which introduced this model, see [22], to model of quantum spinflip scattering in graphene, see [25], in modelling the quantum spin-flip scattering in a Josephson junction, see [21], and finally in modelling the occurrence of Yu-Shiba-Rusinov (YSR) bound states in at the interface of normal metal-superconductor junction, see [26].…”

Section: (Ii) Boundary Conditionsmentioning

confidence: 99%

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Spin-flip scattering engendered quantum spin torque in a Josephson junction

Pal

Benjamin

2019

Proc. R. Soc. A.

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We examine a Josephson junction with two ferromagnet's and a magnetic impurity sandwiched between two superconductors. In such ferromagnetic Josephson junctions equilibrium spin torque exists only when ferromagnet's are misaligned. This is explained via the "conventional" mechanism of spin transfer torque, which owes its origin to the misalignment of two ferromagnet's. However, we see surprisingly when the magnetic moments of the ferromagnet's are aligned parallel or anti-parallel, there is a finite equilibrium spin torque due to the quantum mechanism of spin flip scattering. We explore the properties of this unique spin flip scattering induced equilibrium quantum spin torque, especially its tunability via exchange coupling and phase difference across the superconductors.

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Section: A Hamiltonianmentioning

confidence: 99%

“…1), we will get the wavefunctions for left and right superconductors. The wave function in the left superconductor (for x < − a 2 ) is [21,24]-…”

Section: Wave-functionsmentioning

confidence: 99%

Section: (I) Wave Functionsmentioning

confidence: 99%

“…The boundary conditions can be written as follows [21,24]: at x = −a/2-ψ S L (x) = ψ F 1 (x) (continuity of wave functions) and (dψ…”

Section: (Ii) Boundary Conditionsmentioning

confidence: 99%

Section: (Ii) Boundary Conditionsmentioning

confidence: 99%

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Spin-flip scattering engendered quantum spin torque in a Josephson junction

Pal

Benjamin

2019

Proc. R. Soc. A.

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

et al. 2022

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The 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.

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