Room Temperature Formation of High-Mobility Two-Dimensional Electron Gases at Crystalline Complex Oxide Interfaces

摘要

Transition-metal-oxide materials and their interfaces have played a dominant role in ionic-based solid state electrochemical devices for energy conversion and storage, for example, as the heart of solid oxide fuel cells, gas sensors, and logic devices of electroresistive memories. Complementing these applications in solid state ionics, in recent years there has been rapid progress in exploring oxide interfaces for electronics. In particular, the progress in atomic scale control of complex oxide film growth has resulted in the discoveries of a quasi-two-dimensional electron gas (q2DEG) at the heterointerface between two band-gap insulators of perovskite LaAlO_3 (LAO) and SrTiO_3 (STO), and more recently, a 2DEG with extremely high carrier mobilities, exceeding 100 000 cm~2 V~(-1)s~(-1) at 2 K, at a epitaxial spinel/perovskite interface between gamma-alumina (γ-Al_2O_3, GAO) and STO (GAO/STO).