Structural, electrical, magnetic transport and quantum transport properties of PbPdO2 thin films: Experimental and first-principles study

Abstract

The zero-band gap semiconductor PbPdO₂, with its distinctive energy band structure, holds substantial promise for spintronic device applications. In this study, PbPdO₂ films with different vacancy concentrations and (002) preferred orientation were prepared by sol–gel and pulsed laser deposition (PLD). All films exhibited a positive colossal electroresistance (CER) effect, indicating their potential in spintronics. The critical temperatures (T_c) for films with distinct Pb vacancy concentrations were 260 K, 290 K, and 355 K, respectively. The correlation between T_c and barrier height near O^1- site was revealed. The distance between O2p and Pb 6s6p band centers is calculated by first-principles, and the barrier model determining T_c is confirmed. Additionally, the magnetic properties of PbPdO₂ come from O^1- and are affected by the vacancy concentration. The positive CER effect and magnetic source of PbPdO₂ thin films can be well explained by the internal electric field model and first principles. Finally, a crossover between weak anti-localization (WAL) and weak localization (WL) was observed in PbPdO₂ films, indicating that the quantum transport performance of PbPdO₂ films can be achieved by regulating the vacancy content, which provides a comprehensive guide for the design and optimization of PbPdO₂-based spintronic devices.