低维铁性材料中基于自旋轨道耦合调制的多重极化效应研究

Due to the giant bulk Rashba spin orbit coupling (SOC) in ferroelectric semiconductors and the strong spin-valley coupling in the two-dimensional valleytronic materials, the application of SOC begins to attract the research attention not only in the field of spintronics, but also in the fields of ferroelectrics and valleytronics. How to realize the all-electric control of the charge, spin, and valley polarization through SOC becomes an important problem in the field of information storage. In the present project, we will investigate the Rashba SOC based magnetoelectric coupling effect in the surface of the ferromagnetic film, the influence of the ferroelectricity and the giant bulk Rashba SOC on the electron spin in the ferroelectric semiconductor heterostructure, and the ferrovalley in the one- or two-layer two-dimensional ferromagnetic or ferroelectric materials, which actually includes the SOC-mediated coupling between the magnetic, electric, and valleytronic (MEV) properties. We will explore the manipulation of the different polarizations through SOC and the MEV coupling through SOC. Also, we will design the complex multiferroic materials with MEV coupling, and creat the new device models for the information storage, which can provide the theoretical guidance for the next generation of information storage.

铁电半导体中体相巨Rashba自旋轨道耦合与二维谷电子学材料中强自旋能谷耦合将自旋轨道耦合应用从自旋电子学领域推广至铁电领域和谷电子学。如何通过自旋轨道耦合实现多重极化效应（电荷极化、自旋极化、以及谷极化）的电学调控成为信息领域备受关注的研究问题。本项目拟通过第一性原理计算研究铁磁金属薄膜表面基于Rashba自旋轨道耦合的表面电控磁性机制，铁电半导体异质结界面铁电极化和巨Rashba自旋轨道耦合对电子自旋的调控，以及二维单层/双层铁电、铁磁半导体中的磁电谷耦合效应和铁谷性，揭示自旋轨道耦合对不同极化效应调控的物理本质和其在磁电谷耦合效应中的重要作用，探索具有磁电谷耦合效应的复合多铁材料设计规律，建立新型信息存储元器件模型，为下一代信息存储提供理论指导。

自旋轨道耦合作用将电荷极化、自旋极化，以及谷极化有机结合起来。如何通过自旋轨道耦合实现全电控的极化信息成为信息存储领域一个重要问题。本项目通过第一性原理计算主要研究了三维铁电半导体异质结GeTe/InP、GeTe/MnTe，新型二维铁电半导体异质结In2Se3/MoS2，以及二维铁电半导体GeSe与铁磁半导体VSe2等。主要研究结果有：1)在GeTe/InP、GeTe/MnTe中，阐明了铁电极化对界面Rashba自旋轨道耦合与界面自旋极化的调控，实现了铁电局域场控制自旋极化翻转；2)在二维铁电半导体In2Se3/MoS2，实现了铁电极化控制的能带排列变化；3)在二维铁电GeSe中实现铁电极化调控的谷极化；4)在层间反铁磁耦合的双层VSe2中实现了电场调控自旋极化翻转。通过上述研究，揭示了自旋轨道耦合对不同极化效应调控的物理本质和其在磁电谷耦合效应中的重要作用，探索了具有磁电谷耦合效应的复合多铁材料设计规律，建立了新型信息存储元器件模型。依托项目培养研究生6名，发表学术论文28篇，包括以第一或通讯作者发表的Phys. Rev. Lett.(一篇), PNAS (一篇), Nano Lett.(一篇)等, 研究成果获《中国科学报》头版报道。