Charge transport in oxygen-deficient EuTiO3: The emerging picture of dilute metallicity in quantum-paraelectric perovskite oxides

We report on a study of charge transport in EuTiO3-δ single crystals with carrier density tuned across several orders of magnitude. Comparing this system with other quasicubic perovskites, in particular strontium titanate, we draw a comprehensive picture of metal-insulator transition and dilute metallicity in this ABO3 family. Because of a lower electric permittivity, the metal-insulator transition in EuTiO3-δ occurs at higher carrier densities compared to SrTiO3. At low temperature, a distinct T2 resistivity is visible. Its prefactor A smoothly decreases with increasing carrier concentration in a similar manner in three different perovskites. Our results draw a comprehensive picture of charge transport in doped quantum paraelectrics.