Figure 3

(a) The main panel shows the results of measurements of the differential conductance of device M1 at various temperatures from 3–55 K. The data were obtained for a gate voltage V_g = −6 V, while the Dirac point in this device was positioned at V_g = + 14 V. This condition therefore corresponds to a gate-induced hole concentration of p = 1.44 ⋅ 10¹² cm⁻². The inset shows a rescaling of the data from the main panel, according to which we plot the variation of the bias-induced conductance change (Δg = g(V) − G) as a function of the dimensionless voltage (eV/k_BT). The colors of the different data points correspond to the same temperatures as indicated in the main panel. (b) Data from the inset of (a) replotted with the dimensionless voltage represented on a logarithmic scale to highlight the collapse of the various curves on top of each other. The inset shows the conductance change as a function of the unscaled bias voltage. (c) Similar results as (b) obtained at V_g = + 22 V, corresponding to an electron concentration of n = 5.76 ⋅ 10¹¹ cm⁻² and at V_g = +6 V (inset) corresponding to a hole concentration of p = 5.76 ⋅ 10¹¹ cm⁻².