# Charge transport in oxygen-deficient EuTiO$_3$: the emerging picture of dilute metallicity in quantum-paraelectric perovskite oxides

## TL;DR

This study explores charge transport in oxygen-deficient EuTiO3, revealing how dilute metallicity and metal-insulator transitions occur in quantum-paraelectric perovskite oxides, with insights into the effects of carrier density and permittivity.

## Contribution

It provides a comprehensive analysis of charge transport and metal-insulator transition mechanisms in EuTiO3, comparing it with related perovskites like SrTiO3, highlighting the role of permittivity.

## Key findings

- Metal-insulator transition occurs at higher carrier densities in EuTiO3 than in SrTiO3.
- Low-temperature resistivity exhibits a T^2 dependence with a decreasing prefactor A as carrier density increases.
- The behavior of the resistivity and transition characteristics are consistent across different perovskite materials.

## Abstract

We report on a study of charge transport in EuTiO$_{3-\delta}$ single crystals with carrier density tuned across several orders of magnitude. Comparing this system with other quasi-cubic perovskites, in particular strontium titanate, we draw a comprehensive picture of metal-insulator transition and dilute metallicity in this $AB$O$_3$ family. Because of a lower electric permittivity, the metal-insulator transition in EuTiO$_{3-\delta}$ occurs at higher carrier densities compared to SrTiO$_3$. At low temperature, a distinct $T^2$ 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.