Oxygen Isotope Fingerprints of Electron-Phonon Coupling in SrVO_{3} Films

Transition metals exemplify correlated electronic systems, where electron-electron (e-e) scattering often results in a quadratic temperature dependence of the electrical resistivity, ρ(T)∝T^{2}. In SrVO_{3} (SVO), a material with a V-3d^{1} electronic configuration that ensures metallicity through narrow 3d-t_{2g} bands, a ρ(T)∝T^{2} dependence has been reported. While traditionally attributed to e-e scattering, recent studies suggest that electron-phonon (e-ph) interactions may play a significant role. To unravel the influence of phonon interactions on carrier transport in SVO, we present a comparative study of the transport and optical properties of SVO films with partial substitution of ^{16}O ions by their heavier isotope, ^{18}O. Our findings reveal that ^{18}O substitution induces a change in the slope of dρ(T)/dT at nominal fixed carrier density, highlighting the dominant contribution of e-ph coupling over e-e scattering in determining ρ(T). Furthermore, it is found that the ^{18}O substitution softens the phonon lattice and promotes a reduction in plasma frequency and an increase in the carrier effective mass. These results indicate that the e-ph coupling strength increases upon ^{18}O substitution. Our findings suggest that e-ph interactions may surpass e-e scattering in governing the resistivity of metallic ionic lattices.