Electron-Phonon Origins of Unconventional Resistivity in Moderately Correlated Perovskite Oxides

Transition-metal perovskite oxides exhibit moderately correlated metallic phases, several of which exhibit a T2 resistivity scaling up to temperatures far exceeding the regime where Fermi-liquid electron-electron scattering is expected to dominate. Some of these materials, such as SrMoO₃, also exhibit unexplained ultralow room-temperature resistivity. We demonstrate that in SrMoO₃, SrWO₃, SrTaO₃, SrNbO₃, and SrVO₃ electron-phonon scattering results in quadratic-scaling resistivity due to the shape of the Fermi surface and the thermal activation of optical phonons. We also reveal that the origin of the low resistivity of SrMoO₃ is an overall low electron-phonon coupling strength, and identify SrWO₃ and SrTaO₃ as other possible low-resistivity oxides. Additionally, we find that the strength of electron-phonon coupling is sensitive to structural distortions, energies of optical phonons, and the treatment of electronic correlations. This suggests design principles for finding other ultrahigh conductivity transition-metal oxides, and has significant implications for theoretical interpretation of direct-current resistivity in transition-metal oxides and beyond.