Electric transport as a probe to unveil microscopic aspects of oxygen-depleted YBCO

Abstract

We report on the characterization of Pt-YBa2Cu3O7−δ interfaces, focusing on how oxygen vacancies content (δ) affects electrical transport mechanisms. Our study examines four Pt-YBa2Cu3O7−δ samples with varying δ (0.12 ≤δ≤0.56) using voltage-current measurements across a temperature range. We successfully model the electrical behavior using a Poole-Frenkel conduction framework, revealing that oxygen vacancies create potential wells that trap carriers, directly influencing conduction. We observe that the energy of these traps increases as δ rises, in agreement with a peak previously detected in optical conductivity measurements. This result supports earlier interpretations, strengthening the proposed connection between oxygen vacancies and the ionization energy associated with impurity bands in oxygen-depleted YBa2Cu3O7 − δ.