Apparent Kondo effect in Moiré transition metal dichalcogenide bilayers: Heavy fermions versus disorder

A recent work by Zhao et al. [Nature (London) 616, 61 (2023)] reported the realization of a synthetic Kondo lattice in a gate-tunable Moir & eacute; transition metal dichalcogenide bilayer system. The observation of a Kondo lattice is supported by a plateau (or dip, depending on filling) in the temperature dependence of the resistivity rho(T ) around T* 40 K, which is interpreted as the Kondo temperature scale, and an apparent enhancement of carrier mass extracted from the low-temperature resistivity data, indicating the emergence of "heavy fermions." The latter observation is crucially based on the assumption that the primary resistive scattering mechanism is electron-electron scattering in the underlying Fermi liquid. In this work, we analyze the experimental data under the assumption that the primary resistive scattering mechanism is not electron-electron scattering, but Coulomb scattering by random quenched charged impurities and phonon scattering. We show that a combination of impurity and phonon scattering is a plausible alternative explanation for the observed resistivity that can describe the key features of the experimental data, even if no Kondo lattice has formed, indicating that further theoretical and experimental work is needed to conclusively verify the formation of a Kondo lattice in the work by Zhao et al.