Scalable T² resistivity in a small single-component Fermi surface

Scattering among electrons generates a distinct contribution to electrical resistivity that follows a quadratic temperature (T) dependence. In strongly correlated electron systems, the prefactor A of this T² resistivity scales with the magnitude of the electronic specific heat, γ. Here we show that one can change the magnitude of A by four orders of magnitude in metallic strontium titanate (SrTiO₃) by tuning the concentration of the carriers and, consequently, the Fermi energy. The T² behavior persists in the single-band dilute limit despite the absence of two known mechanisms for T² behavior: distinct electron reservoirs and Umklapp processes. The results highlight the absence of a microscopic theory for momentum decay through electron-electron scattering in various Fermi liquids.