Two-dimensional electron gases (2DEGs) formed at the interface between two oxide insulators provide new opportunities for electronics. However, despite of intensive research, it remains a major challenge to increase the mobility of the 2DEG or to order the emerging properties on demand. Herein, I will present our studies on extreme mobility enhancement at LaMnO3-buffered LaAlO3/SrTiO3 (LAO/STO) interface  and the tunable ground states of diluted LAO/STO interface . Moreover, I will present our recent results on the intrinsic band dispersion of the 2DEGs in these engineered LAO/STO heterostructures, where the LMO buffer layer is found to suppress not only the formation of oxygen vacancies but also the electron-phonon interaction on the STO side, making the buffered sample different from any other STO-based interfaces including the Mn-diluted LAO/STO system.
 Y. Z. Chen et al. Extreme mobility enhancement of two-dimensional electron gases at oxide interfaces via charge transfer induced modulation doping.Nature Mater. 14, 801 (2015)
 Y. L. Gan et al. Diluted Oxide Interfaces with Tunable Ground States, Adv. Mater. 31, 1805970 (2019).