Fig. 4

Effective medium theory graphene drag calculations. a and b show calculations of the effective drag assuming negatively and positively correlated puddles, respectively, with \(n_{{\mathrm{rms}}}^{\mathrm{A,P}} = 6 \times {10}^{10}{\,\mathrm{cm}}^{ - 2}\) in both cases. a uses η in Eq. (16) while b uses the same but with the sign flipped. c EMT drag resistivity calculated as a function of both layer densities at T = 70 K for the same EMT parameters as a. d Contour lines of the plot in (c). The previously curved parts of the contour lines at low density have straightened out and the isolevels that were previously almost touching the axes have moved away from them due to the density-smearing caused by puddles, in agreement with experiments^8,9. Isolevels are drawn every 0.5 Ω from ±1 Ω to ±3 Ω. Interlayer spacing d = 9nm throughout. Scale bars represent \(\tilde \rho _D^{{\mathrm{EMT}}}\) in units of Ω