Tunable two-dimensional electron gas at the interfaces of ferroelectric potassium tantalate niobates

Heterointerfaces in complex oxides have emerged as a promising platform for exploring novel physical phenomena and advancing integrated technologies in sensing, storage, and computing. However, achieving precise control over a two-dimensional electron gas (2DEG) in ferroelectric oxide-based field-effect transistors (FETs) remains a significant challenge. In this study, we report a tunable 2DEG system realized by depositing an amorphous LaAlO_3 layer onto a (001)-oriented ferroelectric potassium tantalate niobate substrate. Interfaces synthesized under high-temperature and high-oxygen-pressure conditions exhibit metallic conduction. Remarkably, well-defined metallic 2DEGs exhibiting pronounced hysteresis behavior and persistent electric-field-modulated resistance are observed below 108 K, with a resistance modulation of 11.6% at 7 K. These findings highlight the potential for extending these phenomena to other oxide-based 2DEG systems and motivate further investigation of ferroelectric metals in complex oxide heterostructures.