Electron-phonon origins of unconventional resistivity in moderately correlated perovskite oxides

TL;DR

This paper explains the unconventional quadratic resistivity in certain perovskite oxides through electron-phonon interactions, highlighting low electron-phonon coupling as key to ultra-low resistivity and offering design principles for high-conductivity materials.

Contribution

It demonstrates that electron-phonon scattering causes quadratic resistivity in these oxides and identifies low electron-phonon coupling as the reason for ultra-low resistivity, informing material design.

Findings

Electron-phonon scattering leads to quadratic resistivity in several perovskite oxides.

Low electron-phonon coupling explains the ultra-low resistivity of SrMoO$_3$.

Structural distortions and phonon energies influence electron-phonon coupling strength.

Abstract

Transition-metal perovskite oxides exhibit moderately correlated metallic phases, several of which exhibit a $T^2$ 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 SrMoO$_3$, also exhibit unexplained ultra-low room-temperature resistivity. We demonstrate that in SrMoO$_3$, SrWO$_3$, SrTaO$_3$, SrNbO$_3$, and SrVO$_3$ 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 SrMoO$_3$ is an overall low electron-phonon coupling strength, and identify SrWO$_3$ and SrTaO$_3$ 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 ultra-high conductivity transition-metal oxides, and has significant implications for theoretical interpretation of direct-current resistivity in transition-metal oxides and beyond.