Josephson current and Andreev states in superconductor–half metal–superconductor heterostructures

Abstract

We develop a detailed microscopic theory describing dc Josephson effect and Andreev bound states in superconducting junctions with a half metal. In such systems, the supercurrent is caused by triplet pairing states emerging due to spin-flip scattering at the interfaces between superconducting electrodes and the half metal. For sufficiently clean metals, we provide a detailed nonperturbative description of the Josephson current at arbitrary transmissions and spin-flip scattering parameters for both interfaces. Our analysis demonstrates that the behavior of both the Josephson current and Andreev bound states crucially depends on the strength of spin-flip scattering, showing a rich variety of features which can be tested in future experiments.

Dephasing-enabled triplet Andreev conductance

“…The triplet superconducting proximity effect [1][2][3] in half metals ͑fully polarized ferromagnets conducting only for one spin direction͒ has received considerable attention recently, both theoretically [4][5][6][7][8][9][10][11] and experimentally. [12][13][14][15] The mechanism behind the effect is the process of triplet Andreev reflection at the half-metal-superconductor interface.…”

The critical current reaction on hydrostatic pressure of a superconductor–semimetal composite

“…[1][2][3][4][5][6][7][8][9][10][11][12] However, despite a vast number of works on the proximity effect in superconductor-ferromagnet junctions, the critical current has been determined only in a few cases. [13][14][15][16][17] The studies have been mostly limited to the measurements of the temperature dependences in heterostructures, which is largely due to the difficulty of measuring the current-voltage characteristics (CVC) in a direction normal to the thin layers.…”

Josephson effect in superconductor/ferromagnet-normal/superconductor structures

“…A possible way to increase the decay length in a ferromagnetic barrier is the use of long-range proximity effect due to induced spin-triplet superconductivity [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40] in structures with nonuniform magnetization. A recent survey of possible structures in which the long-range proximity effect may exists can be found in Refs.…”