Resonant states of a double-barrier junction

Shafranjuk, Serhii; Ketterson, J. B.

doi:10.1103/physrevb.72.024509

Cited by 10 publications

(3 citation statements)

References 33 publications

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“…For the low-transparency junction it is reasonable to assume that the normal scattering processes depending on the quality of the interface and band misfit are equally important [44]. Thus several studies considered the effect of double barriers for metal [45][46][47][48][49], insulator [51], ferromagnet [12,19,40,52,53] and superconductor [44,54] intermediate layers. In general, the supercurrent dependence on the various interface scattering amplitudes is obtained via the scattering matrix approach [3,53,55,56].…”

Section: Introductionmentioning

confidence: 99%

A diagrammatic approach for a clean double-barrier ferromagnetic Josephson junction

Paltoglou¹,

Margaris²,

Flytzanis³

2008

J. Phys. A: Math. Theor.

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We consider a double-barrier superconductor/ferromagnet/superconductor (S/I/F/I/S) ballistic junction with thin insulating layers at the interfaces. Using a diagrammatic approach we obtain the Andreev spectrum and the supercurrent in terms of the S/F interface scattering amplitudes. We use the rules devised for the summation of the multiple scattering diagrams. We especially concentrate on the strong interface scattering and consider the evolution of the supercurrent. We observe that in this case the normal spin-up and spin-down electron (hole) resonances determine well the supercurrent, except near the strong peaks, where the Andreev diagrams are also important. At lower Z ≈ 2 values we also need to keep other closed loops. We consider both the one- and three-dimensional cases. We also consider the case of strong band misfit. The current–phase relation shows a broad range of behavior with 0–π regions and transitions where higher harmonics in the phase contribute dominantly.

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Section: Introductionmentioning

confidence: 99%

A diagrammatic approach for a clean double-barrier ferromagnetic Josephson junction

Paltoglou¹,

Margaris²,

Flytzanis³

2008

J. Phys. A: Math. Theor.

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“…This effect is the superconducting analog of the Bohm resonant tunneling, 15 previously studied in Refs. 16,17,18,19 For corresponding SIFIS junctions, the resonant nature of 0 -π transitions comes into play in the tunnel limit. Triggering of the 0 -π transitions by resonant amplification, as well as the coexistence of stable and metastable 0 and π states in the vicinity of the transition, 20,21 can be fully understood.…”

Section: Introductionmentioning

confidence: 99%

Resonant amplification of the Andreev process in ballistic Josephson junctions

2006

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We study the Josephson effect in ballistic SINIS and SIFIS double-barrier junctions, consisting of superconductors (S), a clean normal (N) or ferromagnetic (F) metal, and insulating interfaces (I). For short SINIS double-tunnel junctions with one channel open for quasiparticle propagation, the critical Josephson current as a function of the junction width shows sharp peaks because of a resonant amplification of the Andreev process: when the quasibound states of the normal interlayer enter the superconducting gap the Andreev bound states are lowered down to the Fermi level. For corresponding SIFIS junctions the quasibound states are spin-split; they amplify the supercurrent less efficiently, and trigger transitions between 0 and π states of the junction. In contrast to SI-NIS junctions, a narrow dip related to the 0π transition opens up exactly at the peak due to a compensation of partial currents flowing in opposite directions. With an increased barrier transparency these features are gradually lost, due to the broadening and overlap of quasibound states. Temperature-induced transitions both from 0 to π and from π to 0 states are studied by computing the phase diagram (with temperature and junction width as the variables) for different interfacial transparencies varying from metallic to the tunnel limit.

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“…11 This effect is the superconducting analogue of the Bohm resonant tunneling, 12 previously studied in Refs. [13][14][15][16]. For ballistic SIFIS nano-junctions (with one channel open for quasiparticle propagation) the resonant nature of 0 − π transitions can be fully revealed in the tunnel limit, including the coexistence of stable and metastable 0 and π states in the vicinity of the transition.…”

Section: Introductionmentioning

confidence: 99%

Resonant amplification of the Andreev process in short Josephson junctions

2005

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We study the Josephson effect in short ballistic SINIS and SIFIS double-barrier junctions, consisting of clean superconductors (S), a normal metal (N) or ferromagnet (F), and insulating interfaces (I). For SINIS double-tunnel junctions, the critical Josephson current as a function of the junction width shows sharp peaks because of resonant amplification of the Andreev process when the quasi-bound states of the normal interlayer enter the superconducting gap and morph into phase-sensitive bound states. For SIFIS double-tunnel junctions the corresponding quasi-bound states are spin-split, they amplify the supercurrent less efficiently, and trigger transitions between 0 and π states of the junction. In contrast to SINIS junctions where the critical current reaches a peak value when the Andreev bound states cross the Fermi surface, here a narrow dip opens up exactly at the peak due to compensation of partial currents flowing in opposite directions. With increased barrier transparency, the described mechanism is modified by the broadening and overlap of quasi-bound states. Temperature-induced transitions both from 0 to π and from π to 0 states are studied by computing the phase diagram (with temperature and junction width as the variables) for different interfacial transparencies varying from transparent metallic to the tunnel limit.

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Resonant states of a double-barrier junction

Cited by 10 publications

References 33 publications

A diagrammatic approach for a clean double-barrier ferromagnetic Josephson junction

A diagrammatic approach for a clean double-barrier ferromagnetic Josephson junction

Resonant amplification of the Andreev process in ballistic Josephson junctions

Resonant amplification of the Andreev process in short Josephson junctions

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