稀磁半导体低维结构的自旋调控及器件应用

The applicant has carried out the systematic work in the field of dilute magnetic semiconductors (DMS) as supported by Youth Scientific Fund (YSF) Project, and obtained several creative results. The applicant has published 8 papers in the Journals such as JACS, Small, OE, JPD, and APL, and gained 22-times citations by others. The applicant mainly developed electron beam image and spectroscopic examination technique applied to ZnO-based DMS microstructures. He firstly employed low-loss electron energy loss spectroscopy to study the electronic structures of individual DMS nanoparticles, achieved dopant energy level observation with the nanoscale spatial resolution and near optical energy resolution, and proposed band-coupling room-temperature magnetism directly from electronic structures based on the first-principles calculations..In this Project, the applicant will continue the preliminary results obtained from the YSF Project and develop the high-quality fabrication techniques for (Zn,Co)O DMS, i.e., the controlled chemical growth for one-dimensional nanostructures and laser molecular beam epitaxy growth for two-dimensional thin films. Through manipulation of the external fields, the applicant will study quantum physical characteristics, such as spin transport, charge transfer, spin-orbit coupling, and dephasing. At the same time, the applicant will develop the related prototype device fabrication procedure and technology, and conduct the in-depth experimental study on the spin manipulation in (Zn,Co)O low-dimensional structures and their potential applications in spintronic devices.

申请人已在青年科学基金项目支持的稀磁半导体(DMS)及相关领域开展了系统工作，取得了若干有创新性的研究成果。两年多来发表论文8篇，包括JACS、Small、OE、JPD各一篇和APL两篇，论文已他引22次。主要发展了ZnO DMS的微结构电子谱像检测技术，首先将二次电子诱发的电子能量损失特征应用于单个DMS纳米颗粒的电子结构精细研究，实现了纳米空间分辨和近光学能量分辨的掺杂剂能级观察；并结合第一性原理计算，直接从电子结构角度提出了能带耦合的室温磁性机制。.本项目将继续沿着青年科学基金项目的初步结果，发展制备高质量(Zn,Co)O一维纳米结构的可控化学生长和二维薄膜结构的激光分子束外延生长技术，通过外场调控，研究自旋输运、电荷转移、自旋轨道耦合及退相干等方面的量子物理特性，同时发展相关原型器件的制备工艺和技术，深入开展(Zn,Co)O低维结构的自旋调控及潜在的自旋电子学器件应用的实验研究。

我们在本项目所支持的稀磁半导体低维结构及相关领域开展了系统工作，完成了预定的研究任务，取得了若干有创新性的研究成果。四年来发表论文17篇，其中第一作者或通讯作者论文13篇，包括发表在Adv. Mater.、Adv. Electron. Mater.、IEEE Electron Dev. Lett.、Appl. Phys. Lett.、Sci. Rep.、J. Phys. Chem. C等国际一流期刊上的论文，并合作编写专著《量子物理》教材一部，申请国家发明专利2项，独立建设一套激光分子束外延单晶薄膜生长系统。我们主要实现了高质量的氧化物和拓扑绝缘体的稀磁半导体低维纳米结构（含一维纳米线、二维薄膜等）的生长，主要材料类型有Co掺杂(La,Sr)TiO3纳米晶、Sm掺杂Bi2Se3拓扑绝缘体单晶及纳米薄膜、Fe掺杂In2O3和Nd掺杂In2O3纳米线、Fe掺杂Bi2Se3纳米线及块体单晶和Co掺杂ZnO纳米线等，利用微加工技术和低温输运测量实现了基于本征拓扑绝缘体BiSbTeSe2自旋阀器件的自旋极化电流调控。同时深入理解了上述几类稀磁半导体材料中磁性起源特征和相关耦合机制，揭示了其自旋器件的潜在应用。除此之外，还研究了ZnO、(La,Sr)MnO3、LaMnO3、LaAlO3、Fe3O4和YIG等自旋氧化物薄膜的外延生长，研究了石墨烯表面缀饰纳米粒子后的奇异量子输运行为，并深入研究了新型拓扑狄拉克半金属量子材料（如ZrSiS和Cd2As3）的磁输运性质。该项目所获得的这些成果预示了稀磁半导体、磁性拓扑绝缘体、拓扑半金属等量子材料在低耗散新型自旋电子器件中的潜在应用。