Spin-switch Josephson junctions with magnetically tunable sin( δφ/n ) current-phase relation
Year: 2017
Type: article
Abstract: With a combination of simple analytical arguments and extensive numerical simulations, we theoretically propose a Josephson junction with $n+1$ superconductors where the current-phase relation can be toggled in situ between a $sin(\ensuremath{\delta}\ensuremath{\varphi})$ and $sin(\ensuremath{\delta}\ensuremath{\varphi}/n)$ shape using an applied magnetic field. Focusing in particular on the case $n=2$, we show that by using realistic system parameters such as unequal interface transparencies, the $sin(\ensuremath{\delta}\ensuremath{\varphi}/2)$-shaped solution retains its $2\ensuremath{\pi}$ periodicity due to discontinuities at $\ensuremath{\delta}\ensuremath{\varphi}=\ifmmode\pm\else\textpm\fi{}\ensuremath{\pi}$. Moreover, we demonstrate that as one toggles between the $sin(\ensuremath{\delta}\ensuremath{\varphi})$- and $sin(\ensuremath{\delta}\ensuremath{\varphi}/2)$-shaped solutions, the system acts as an on-off switch, and can achieve more than two orders of magnitude difference between the supercurrent in the on and off states. Finally, we argue that the same approach can be generalized to switchable $sin(\ensuremath{\delta}\ensuremath{\varphi}/n)$ junctions for arbitrary integers $n$, which we motivate by analytically solving the Josephson equations for double- and triple-barrier junctions.
Authors: Jabir Ali Ouassou, Jacob Linder
Institution: Norwegian University of Science and Technology
Language: Latvian
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: Norges Forskningsråd
Awards: G5147281314, G5258689067
OpenAlex ID: W2643373326