Fig. 4: Drive dependence of thermoelectric current.
From: Thermoelectric current in a graphene Cooper pair splitter
a Upper curves: thermoelectric current in the left quantum dot IL,exp vs. gate voltage Vsg,L measured at heating voltages Vh = [5, 9, 19, 25, 29] mV, where Vh = 5 mV is the blue curve and 29 mV is the red curve. We estimate the induced temperature difference between the left and right quantum dots to be TL − TR ≃ 17 mK for Vh = 5 mV, and TL − TR ≃ 59 mK for Vh = 29 mV. Middle curves: theory predictions based on the coherent model (see Supplementary Note 4) for the thermoelectric current IL,theory plotted in the same manner as the upper curves for Vh = [5, 10, 20, 25, 30] mV. The gap of Al/Ti leads is set to Δ0 = 150 μeV at T = 0 while the BCS gap formula Δ(TS) with TS = (TL + TR)/2 defines the T dependence. Lowest curve: experimental conductance of the left quantum dot. b Incoherent modeling for the low temperature regime: theoretical fits (dashed) to the measured thermoelectric currents IL and conductance gL (solid) at Vh = 7 and 11 mV, blue and red curves, respectively. The model is based on the assumption that the system may be split into the coherent subsystems, which, in turn, are joined incoherently into a circuit. Details of the model and fitting parameters are given in Supplementary Note 5.
