Fig. 4: Magnetic field dependence of the Coulomb gap.
From: A magnetically-induced Coulomb gap in graphene due to electron-electron interactions
a The dependence of current, I, on magnetic field, B, I(B) (and I(1/B) inset), with applied gate, Vg = 1.65V, and bias voltages Vb = 0.6 mV at temperatures T = 7 K (red), 2 K (green) and 0.3 K (blue). The peaks are labelled p = 1, 2, 3. b The conductance measured as a function of Vb, G(Vb), when Vg = 1.65 V and T = 0.3 K for B = 1.3, 2 and 3.75 T. c Colour map of G(Vb, B) measured when Vg = 1.65 V and T = 0.3 K. Colour bar shows the amplitude of the conductance in the colour map. d Red data points show the maximum in ΔVb at T = 0.3 K for the B-fields shown in (b), the blue data points show the measured dependence of the gap width ΔVb over the full range of B. The blue curve is a theoretical fit to the measurements given by Eq. (7). The inset shows the dependence ΔVb(B) for the fractional filling of the Landau level with index 1 given by Eq. (9). Error bars estimate the uncertainty in determining the peak-to-peak width of the Coulomb gap from the measured data.
