Fig. 3

Colour map of differential conductance for Device 2 as a function of the two gate voltages. a Diagram of the double gated Device 2 showing the layer and voltage configuration where V_b, \(V_{\mathrm{g}}^{\mathrm{t}}\) and \(V_{\mathrm{g}}^{\mathrm{b}}\) are the applied bias, top gate and bottom gate voltages. b Schematic diagram showing the alignment of the chemical potentials in the bottom and top layers, μ_b and μ_t, when V_b = 0. c Colour map (log-scale) of \(G\left( {V_{\mathrm{g}}^{\mathrm{b}},V_{\mathrm{g}}^{\mathrm{t}}} \right)\) when the bias voltage, V_b = 0, solid white curves show calculated positions when the chemical potential in the top and bottom electrodes intersect the Dirac points in those layers. J,K and L,M indicate the loci where there is a sharp increase in conductance corresponding to the threshold where electrons can tunnel directly between the bands of the two twisted graphene electrodes