Kondo scattering versus weak localization in overdoped infinite-layer La1−xSrxNiO2 thin films

The metal-insulator transition of overdoped infinite-layer nickelates at low temperature has not been clearly explained. In this study, magnetoresistance and the corresponding conductance correction of the overdoped infinite-layer $\mathrm{L}{\mathrm{a}}_{1\ensuremath{-}x}\mathrm{S}{\mathrm{r}}_{x}\mathrm{Ni}{\mathrm{O}}_{2}$ films were fitted by the Kondo model and the Hikami-Larkin-Nagaoka formula, respectively. Moreover, the temperature dependence of resistivity is well modeled using contributions mainly from Kondo scattering and weak localization (WL). The results show that the metal-insulator transition of the overdoped infinite-layer $\mathrm{L}{\mathrm{a}}_{1\ensuremath{-}x}\mathrm{S}{\mathrm{r}}_{x}\mathrm{Ni}{\mathrm{O}}_{2}$ films at low temperature is mainly due to the combined effect of Kondo scattering and WL. With the increase of Sr doping concentration, the contribution from the Kondo scattering gradually weakens and WL becomes dominant, which is consistent with the predictions of the self-doped Mott-Kondo theory. Our work contributes to elucidating the physical properties of overdoped $\mathrm{L}{\mathrm{a}}_{1\ensuremath{-}x}\mathrm{S}{\mathrm{r}}_{x}\mathrm{Ni}{\mathrm{O}}_{2}$ infinite-layer thin films, providing experimental evidence for understanding the scattering mechanisms of nickelates.