Fig. 2: Experimental observations are consistent with the electron-phonon scattering theory.

The electron–phonon scattering theory (left panels) correctly captures the a carrier density and b temperature dependence of experimentally observed resistivity (middle panels), unlike the Planckian theory (right panel) that shows a stronger density dependence. Experimental data is taken from ref. ⁴² for θ = 1.11^∘ (comparison for devices with other twist angles is shown in the Supplementary Information). Solid lines in the electron–phonon and Planckian theory are for a two-band effective model that includes the van Hove singularity, while the dashed lines are for the linear Dirac model. For electron–phonon scattering, the linear-in-T resistivity at low temperature is captured by the Dirac model, while the saturation at higher temperature requires the van Hove singularity. For the Planckian theory, the Dirac model and the two-band model are quantitatively similar and show much stronger density dependence compared to the experiment. In this case, the saturation at high temperature is set not by the van Hove singularity, but by a universal value \(\rho (T\to \infty )=C/(8{{{{{{\mathrm{ln}}}}}}}\,2)h/{e}^{2}\) (the coefficient C ≤ 1 for Planckian dissipation). For most experimental data, including those shown here, C ≥ 1. Taken together with the weak density dependence seen experimentally, this suggests that phonon scattering rather than Planckian dissipation is the dominant scattering mechanism at play in twisted bilayer graphene.