Figure 5.

Magnetoresistance measurements of the best sample at different temperatures. (a) Longitudinal and transverse resistances of low p-type doped (n_s = 8 × 10¹¹ cm^-2) epitaxial monolayer versus applied magnetic field B, at different temperatures. (b) Temperature dependence of the resistivity ρ_xx of a graphene ribbon at different magnetic field values close to the filling factor v = 3. The slope in the semilog scale gives the activation energy E_a, which is the energy difference between the Fermi energy and the mobility edge of the second (N = 1) Landau level.