Common Fermi-liquid origin of T2 resistivity and superconductivity in n-type SrTiO3

A detailed analysis is given of the T-2 term in the resistivity observed in electron-doped SrTiO3. Band-structure data are presented that provide values for the bare mass, density of states, and plasma frequency of the quasiparticles as functions of doping. It is shown that these values are renormalized by approximately a factor of two due to electron-phonon interaction. It is argued that the quasiparticles are in the antiadiabatic limit with respect to electron-phonon interaction. The condition of antiadiabatic coupling renders the interaction mediated through phonons effectively nonretarded. We apply Fermi-liquid theory developed in the 70's for the T-2 term in the resistivity of common metals, and combine this with expressions for T-c and with the Brinkman-Platzman-Rice (BPR) sum rule to obtain Landau parameters of n-type SrTiO3. These parameters are comparable to those of liquid He-3, indicating interesting parallels between these Fermi liquids despite the differences between the composite fermions from which they are formed.