Fig. 7.

Four terminal transport measurements. a Resistivity as a function of back gate voltage at room temperature. Inset: optical image of the measured Hall bar with W = 24 μm. Scale bar 10 μm. b Mobility μ = σ/(ne) at room temperature. n is extracted from a Hall measurement with a B = 0.5T out of plane magnetic field. c Resistivity of the sample at 9 K. Inset: conductivity as a function of carrier density close to the CNP, showing the extraction of n^*. The dashed lines represent extrapolated fits to the linear and sloped portions of the conductivity. d Extracted mobility as a function of charge carrier density at 9 K. e Room temperature mobility of 17 encapsulated SLG samples as a function of the bottom hBN thickness. The mobility is the peak value of the density dependent mobility, i.e., the mobility close to the CNP. f Mean free path as a function of carrier density for different temperatures for a sample with width W = 18 μm