In a Josephson junction, the current phase relation relates the phase variation of the superconducting order parameter, φ, between the two superconducting leads connected through a weak link, to the dissipationless current . This relation is the fingerprint of the junction. It is usually dominated by a sin(φ) harmonic, however its precise knowledge is necessary to design superconducting quantum circuits with tailored properties. Here, we directly measure the current phase relation of a superconducting quantum interference device made with gate-tunable graphene Josephson junctions and we show that it can behave as a sin(2φ) Josephson element, free of the traditionally dominant sin(φ) harmonic. Such element will be instrumental for the development of superconducting quantum bits protected from decoherence.
@article{arxiv.2405.13642,
title = {Direct measurement of a $\sin(2\varphi)$ current phase relation in a graphene superconducting quantum interference device},
author = {Simon Messelot and Nicolas Aparicio and Elie de Seze and Eric Eyraud and Johann Coraux and Kenji Watanabe and Takashi Taniguchi and Julien Renard},
journal= {arXiv preprint arXiv:2405.13642},
year = {2026}
}
Comments
15 pages, 3 figures, Supplemental Material in Ancillary files