Extended Data Fig. 1 Device image and reproduction of selected measurements across contact pairs. a, Optical micrograph of the device from the main text with the source, drain and voltage probes labelled. Scale bar, 5 μm. b, Measurement of ρxx versus Vb at Vt = 2.30 V for selected values of Vsg, showing that the AM and SC resistance values are independent of the silicon gate voltage. The exception is Vsg = −20 V, at which the contacts become insulating and the measurement for all Vb is unreliable. c, Maps of ρxx for all three longitudinal voltage pairs as a function of Vt and Vb at base temperature. All panels below each map correspond to the associated contact pair. d, Measurements of ρxx versus Vb and B⊥ taken at B∥ = 0, Vt = 1.10 V. e, Measurements of dV/dI versus Vb and Idc taken at Vt = 3.00 V, B⊥ = 0 and B∥ = 1.0 T. f, Measurements of dV/dI versus Idc and T taken at Vt = 3.00 V, Vb = −3.08 V, B⊥ = 0 and B∥ = 350 mT. g, Traces of dV/dI versus Idc at selected T corresponding to the colour-coded lines in f...