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We investigate the transport properties of magnetic Josephson junctions. In order to capture realistic material band structure effects, we develop a numerical method combining density functional theory and Bogoliubov-de Gennes model. We demonstrate the capabilities of this method by studying Nb/Ni/Nb junctions in the clean limit. The supercurrent through the junctions is calculated as a function of the ferromagnetic Ni thickness, magnetization, and crystal orientation. We identify two generic mechanisms for the supercurrent decay with ferromagnet thickness: (i) large exchange splitting may gap out minority or majority carriers leading to the suppression of Andreev reflection in the junction, (ii) loss of synchronization between different modes due to the significant dispersion of the quasiparticle velocity with the transverse momentum. Our results are in good agreement with recent experimental studies of Nb/Ni/Nb junctions. The present approach opens a path for material composition optimization in magnetic Josephson junctions and superconducting magnetic spin valves.
We report on the fabrication and measurements of planar mesoscopic Josephson junctions formed by InAs nanowires coupled to superconducting Nb terminals. The use of Si-doped InAs-nanowires with different bulk carrier concentrations allowed to tune the
We demonstrate that perfect conversion between charged supercurrents in superconductors and neutral supercurrents in electron-hole pair condensates is possible via a new Andreev-like scattering mechanism. As a result, when two superconducting circuit
We study mesoscopic fluctuations and weak localization correction to the supercurrent in Josephson junctions with coherent diffusive electron dynamics in the normal part. Two kinds of junctions are considered: a chaotic dot coupled to superconductors
The Josephson effect is a fundamental quantum phenomenon consisting in the appearance of a dissipationless supercurrent in a weak link between two superconducting (S) electrodes. While the mechanism leading to the Josephson effect is quite general, i
The critical current response to an applied out-of-plane magnetic field in a Josephson junction provides insight into the uniformity of its current distribution. In Josephson junctions with semiconducting weak links, the carrier density and, therefor