Messelot Simon, Aparicio Nicolas, de Seze Elie, Eyraud Eric, Coraux Johann, Watanabe Kenji, Taniguchi Takashi, Renard Julien
University Grenoble Alpes, CNRS, Grenoble INP, <a href="https://ror.org/04dbzz632">Institut Néel</a>, 38000 Grenoble, France.
Research Center for Electronic and Optical Materials, <a href="https://ror.org/026v1ze26">National Institute for Materials Science</a>, 1-1 Namiki, Tsukuba 305-0044, Japan.
Phys Rev Lett. 2024 Sep 6;133(10):106001. doi: 10.1103/PhysRevLett.133.106001.
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.
