The origin of magnetic ordering and reduced mobility in KTaO3-based 2DEGs: Interfacial interdiffusion

Abstract

Recently, KTaO3 (KTO)-based 5d two-dimensional electron gases (2DEGs), characterized by robust spin–orbit coupling, have emerged as promising candidates for future spintronic devices. However, the carrier mobility of KTO-based 2DEGs is typically lower than that of SrTiO3-based 2DEGs, which limits their further development. It is imperative to explore the underlying causes of diminished carrier mobility and devise strategies to augment it. In addition, the genesis of magnetism within KTO-based 2DEGs remains ambiguous. In this study, the 2DEG within the amorphous-EuTiO3/KTO (a-ETO/KTO) heterostructure demonstrates a high electron mobility of 289.1 cm2 V−1 s−1, which exhibits a significant decrease as the film growth temperatures increase. This decrease can be primarily ascribed to electron scattering by impurities, which is induced by the amplified interfacial element interdiffusion at a higher film growth temperature. In addition, the magnetism of 2DEGs for samples grown at different temperatures shows an increasing trend with growth temperatures, which is predominantly derived from the interdiffusion of Eu atoms. This study provides an in-depth analysis of the origin of magnetic ordering and reduced mobility in KTO-based 2DEGs, which will promote the further development of 2DEGs for future applications in electronic devices.