Intermediate-temperature resistivity in the electron-doped cuprate La2-xCexCuO4+δ: Insights into the doping-independent T2 behavior

The analysis of relationships among resistivity, temperature, and doping in the electron-doped cuprate La2-xCexCuO4+δ (LCCO) has yielded profound insights into its low-temperature transport behavior. Within the intermediate-temperature range of 70-200 K, a ubiquitous T2 resistivity behavior emerges, distinct from the linear resistivity characteristic of the strange metal state below 50 K. Despite its prominence, the origin of the T2 resistivity at various doping levels remains elusive, prompting debates on the sufficiency of Fermi-liquid theory. Here, a systematic electrical transport on epitaxial composition-spread films reveals a doping-independent intermediate-temperature region of T2 behavior in the phase diagram of overdoped LCCO. This observation suggests a topologically stable Fermi surface with strong electron-phonon coupling. The Fermi liquid of polaronic quasiparticles and their interactions provides a plausible framework to understand the intermediate-temperature T2 behavior in cuprate superconductors.