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

TL;DR

This paper demonstrates that the T^2 resistivity and superconductivity in n-type SrTiO3 originate from a common Fermi-liquid mechanism, supported by novel bandstructure data and theoretical analysis.

Contribution

It introduces a detailed Fermi-liquid analysis linking T^2 resistivity and superconductivity in SrTiO3, incorporating new bandstructure data and the anti-adiabatic electron-phonon interaction regime.

Findings

Quasiparticle parameters are renormalized by electron-phonon interaction.

Quasiparticles are in the anti-adiabatic limit, making phonon interactions effectively non-retarded.

Landau parameters in SrTiO3 are comparable to those of liquid 3He.

Abstract

A detailed analysis is given of the T^2 term in the resistivity observed in electron-doped SrTiO3. Novel bandstructure data are presented, which provide values for the bare mass, density of states, and plasma frequency of the quasiparticles as a function of doping. It is shown that these values are renormalized by approximately a factor 2 due to electron-phonon interaction. It is argued that the quasiparticles are in the anti-adiabatic limit with respect to electron-phonon interaction. The condition of anti-adiabatic coupling renders the interaction mediated through phonons effectively non-retarded. 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 Tc 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 3He, indicating interesting parallels between these Fermi-liquids despite the differences between the composite fermions from which they are formed.