Regensburg 2019 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 55: Superconductivity: Tunneling and Josephson Junctions

TT 55.13: Vortrag

Donnerstag, 4. April 2019, 12:45–13:00, H23

Manipulation of Cooper pair entanglement in hybrid topological Josephson junctions — Gianmichele Blasi, Fabio Taddei, Vittorio Giovannetti, and •Alessandro Braggio — NEST, Scuola Normale Superiore and Istituto Nanoscienze-CNR, I-56126 Pisa, Italy

We investigated the supercurrent in a hybrid topological Josephson junction consisting of two planes of topological insulator (TI), which allows both local (LAR) and crossed (CAR) Andreev processes at the interfaces with two conventional s-wave superconductors. We describe the effects of local Rashba-like and Zeeman-like fields applied to the edge states. In particular, we demonstrate that the Rashba-like field, as induced by local gating, allows the manipulation of the entaglement symmetry of non-local Cooper pairs associated to the CAR process. We establish a connection between the Josephson current-phase relationship of the system and the action of the two local fields, finding that they selectively modify the LAR or the CAR contributions. Remarkably, we find that the critical current of the junction takes a very simple form which reflects the change in the symmetry occurred to the entangled state and allows to determine the microscopic parameters of the junction.

[1] G. Blasi, F. Taddei, V. Giovannetti, A. Braggio, arxiv:1808.09709