Figure 2: Redistribution of supercurrent as the gap opens in bilayer graphene.
From: Edge currents shunt the insulating bulk in gapped graphene
(a) Resistance R of one of our Josephson junctions (3.5 μm wide and 0.4 μm long) above the critical T as a function of top and bottom gate voltages. The dashed white line indicates equal doping of the two graphene layers with carriers of the same sign. The dashed green line marks the CNP (maximum R) and indicates equal doping with opposite sign carriers. (b) Differential resistance dV/dI measured along the green line in a at low T and in zero B. Transition from the dissipationless regime to a finite voltage drop shows up as a bright curve indicating Ic. The vertical line marks the superconducting gap of our Nb films. (c) Interference patterns in small B. The top panel is for the case of high doping [Ic(B=0) ≈10 μA] and indistinguishable from the standard Fraunhofer-like behaviour illustrated in Fig. 1d. The patterns below correspond to progressively larger Egap. Changes in the phase of Fraunhofer oscillations are highlighted by the vertical dashed white lines. (d) Extracted spatial profiles of the supercurrent density (Js) at the CNP for the three values of D in c.
