Electrical transport behavior of the oxygen vacancies-rich LaAlO3/SrTiO3heterogeneous interface at high temperature

Dianbing Luo; Yunhai Chen; Yifei Wang; Xinyu Cao; Phyo Aung; Kexin Jin; Shuanhu Wang

doi:10.1088/1361-648X/ad0d29

Electrical transport behavior of the oxygen vacancies-rich LaAlO₃/SrTiO₃heterogeneous interface at high temperature

J Phys Condens Matter. 2023 Nov 23;36(9). doi: 10.1088/1361-648X/ad0d29.

Authors

Dianbing Luo¹, Yunhai Chen¹, Yifei Wang¹, Xinyu Cao¹, Phyo Aung¹, Kexin Jin¹, Shuanhu Wang¹

Affiliation

¹ Shaanxi Key Laboratory of Condensed Matter Structures and Properties and MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an 710072, People's Republic of China.

PMID: 37972407
DOI: 10.1088/1361-648X/ad0d29

Abstract

Oxygen vacancy is one of the original mechanisms of the two-dimensional electron gas (2DEG) at the LaAlO₃(LAO) and SrTiO₃(STO) heterogeneous interface, and it has an important impact on the electrical properties of LAO/STO heterojunction. In this work, the LAO thin films were grown on the STO substrates by pulsed laser deposition, and the electrical transport behavior of the LAO/STO interface at high temperature and high vacuum were systematically studied. It was found that at high temperature and high vacuum, the oxygen vacancies-rich LAO/STO heterojunction would undergo a metal-insulator transition, and return to metal conductivity when the temperature is further increased. At this time, the conduction mechanism of the sample is drift mode and the thermal activation energy is 0.87 eV. While during the temperature decreasing, the conduction mechanism would transfer to hopping conduction with the thermal activation energy of 0.014 eV and the resistance would increase dramatically and present a completely insulated state. However, when the oxygen vacancies-rich sample is exposed to air, the resistance would gradually decrease and recover.

Keywords: disorder degree; metal–insulation transition; oxygen vacancy; two-dimensional electron gas.