Direct measurements of the current-phase relation in graphene Josephson junctions

The current-phase relation (CPR) of a Josephson junction can provide key information about the microscopic processes and symmetries that influence the supercurrent. In this talk, we present CPR results on Josephson junctions containing single-layer graphene as a weak link. The measurements are based on a phase-sensitive SQUID technique in which we determine the supercurrent amplitude and phase as a function of both temperature and electrostatic doping (gate voltage). We present CPR measurements of narrow junctions (5 - 12 $\mu$m) in the diffusive regime spanning the temperature range of 25 - 800 mK. We compare these data with previous CPR measurements on wide junctions in the temperature range of 800 - 900 mK.