过渡金属氧化物异质界面二维电子气的离子液体辅助的多场调控

Transition-metal oxide heterointerfaces have become the research cutting edge of the correlated oxide electronic system. Manipulating the high-mobility two-dimensional electron gas (2DEG) at interfaces will have the great values to the fundamental research as well as the low-energy-consumption device applications, which provides the good opportunities for the development of the information technology in the post-Moore era. However, the capability to manipulate carriers by using the traditional field-effect frame based on dielectric materials is usually weak, which seriously restricts the practical device applications of the interfacial 2DEG. In this Project, in order to solve this key problem, we shall carry out the research of ionic-liquid assisted multiple field (i.e., electric field, magnetic field and optical field, etc.) manipulation. We plan to employ pulsed laser deposition technique to fabricate the low-dimensional transition-metal oxide heterojunction thin film system with the atomic-level accurate control and then induce the high-mobility 2DEG. We shall take the SrTiO3-based heterointerface as a representative that we are very familiar with. We shall use the ionic-liquid assisted multiple field manipulation techniques to effectively control 2DEG under the synergetic work of the electric field, magnetic field and optical field, etc., thus achieving the larger-scale regulation of interface’s carrier concentration, controlling the Rashba spin-orbital coupling interactions, as well as inducing and modulating the interface’s novel quantum phenomena, such as quantum Hall effect and superconducting behavior, and finally disclosing the underlying microscopic physics. Eventually, we shall fabricate the new quantum devices based on the 2DEG at the correlated oxide heterointerfaces.

过渡金属氧化物异质界面是关联氧化物电子体系的研究前沿，调控界面高迁移率的二维电子气无论在基础研究还是低功耗器件应用方面均极具价值，为后摩尔时代电子信息技术的发展提供机遇。然而，使用传统介电材料的场效应结构调控载流子的能力通常较弱，这严重制约了界面二维电子气的实际器件应用。本项目针对这一问题开展离子液体辅助的电场、磁场和光场等多场调控的研究。我们拟采用脉冲激光沉积技术制备原子级精控的低维过渡金属氧化物异质结薄膜体系（以具有前期工作基础的SrTiO3基异质界面为代表），诱导出高迁移率的二维电子气。采用离子液体辅助的多种场调控技术，对二维电子气进行电场、磁场和光场等协同作用下的有效调控和探索，实现界面载流子浓度的更大范围调节、Rashba自旋轨道耦合作用的有效调控、诸如量子霍尔效应、超导等新奇量子效应的诱导与调制，揭示其微观物理机制。最后探索基于关联氧化物异质界面二维电子气的新型量子器件的研制。

我们在本项目所支持的关联电子氧化物领域开展了离子液体辅助的多场调控研究，完成了预定的研究任务，取得了若干有创新性的研究成果。四年来发表SCI论文32篇，其中通讯作者（含共同通讯）论文22篇，包括发表在Adv. Mater.、ACS Appl. Mater. Interfaces、J. Phys. Chem. Lett.、Adv. Electron. Mater.、Adv. Mater. Interfaces、Appl. Phys. Lett.、J. Phys. Chem. C、Appl. Surf. Sci.、Nanotechnology、Chin. Phys. Lett.等国际、国内一流期刊上的论文，并编写专著《Spintronic 2D Materials: Fundamentals and Applications》一章（出版社Elsevier），获得授权国家发明专利4项，自主搭建一套低温强场光电集成输运测量系统，培养3名博士生及4名硕士生毕业。在该项目支持下，我们成功获得了一系列过渡金属氧化物异质界面二维电子气、自旋极化二维电子气及其包含离子液体电场调控、光场调控在内的多种外场调控，同时关注关联氧化物薄膜的界面磁性，探索新材料、新物理和新效应；并且还制备出了一系列高质量的大面积拓扑单晶薄膜及其异质结构，深入探索了拓扑薄膜的异质结构筑和微波探测应用；并由此制备出了基于关联氧化物异质界面的新型自旋电子原型器件。该项目的研究为关联氧化物材料、拓扑电子材料及其它体系在自旋电子器件的应用奠定了坚实的基础。