基于高电导率二维拓扑材料的磁矩电学调控研究

Control of magnetization based on high spin-conversion-rate（SCR）material is a hot topic in the field of high performance magnetic information storage. Topological materials possess the highest SCR in known materials, and are expected to achieve high speed and low energy consumption operation. However, the control of Magnetization based on topological materials usually requires magnetic field assistance, which greatly restricts the device integration. WTe2 and other two-dimensional topological materials have excellent characteristics such as high conductivity, out-of-plane spin generation and electric field control. They are expected to achieve all-electrical Magnetization control in the absence of external magnetic field. This project aims to study the Magnetization control by current and electric field based on WTe2 and other two-dimensional topological materials with high conductivity. The main contents of the study include: 1) the key factors of system determing the efficiency of out-of-plane spin generation, optimize the allocation to ensure the magnetization switching can be directional under zero magnetic field; 2) manipulate the conductivity and SCR by electric field and many other fields to minimize the energy consumption factor and solve the heating problem of device, realize the magnetization reversal regulation and auto-oscillation by current and electric field; 3) develop new magnetic memory devices and frequency-tunable nano-sized microwave devices based on two-dimensional topological materials. The successful implementation of this project can enrich the research contents of the magnetization control by electrical regulation, and provide valuable references for the design and application of high-performance magnetic memory devices.

基于高自旋转换率材料的磁矩电学调控是当前高性能磁存储领域研究的热点。拓扑材料拥有已知材料中最高的自旋转换率，有望实现高速、低能耗的磁存储操作。但拓扑材料对磁矩的调控一般需要磁场辅助，极大限制了器件集成度。高电导率二维拓扑材料（如WTe2、NbSe2、Bi2Se3等）具有高自旋转换率、可产生面外自旋、可电场调控等优异特性，有望实现无需外加磁场的全电学磁矩调控。本项目拟基于高电导率二维拓扑材料开展磁矩的电学调控研究。研究内容主要包括：1）基于材料的高电导率和高自旋转换率优势，实现低能耗的磁矩电学调控；2)利用二维体系可进行电场调控的特性，通过离子液体辅助，大范围调节材料的电导率和自旋转换率，进一步降低能耗，实现磁矩翻转和自发振荡的电流、电场双调控；3）研究面外自旋产生的物理机制和调控，通过晶向和电场等因素的优化配置，实现无需外加磁场的全电学磁矩调控，为开发新型高密度磁存储器件提供有价值的参考。

基于高自旋转换率材料的磁矩电学调控是当前高性能磁存储领域研究的热点。申请人主要围绕二维体系开展磁矩调控和其在信息存储方面应用的前瞻性探索，完成了预定的研究目标，取得了若干创新性成果。4年间，以（共同）通讯作者发表论文35篇；申请发明专利6项，其中1项授权；培养博士生3名，硕士生12名。申请人通过机械剥离、微纳加工等技术手段制备相关基础材料和测试器件，在Fe3GeTe2等单一材料或铁磁/非铁磁异质结中，对材料性质进行系统表征，利用电场等调控手段，结合第一性原理计算等，总结梳理材料和器件的本征性能、电荷-自旋转换、能带结构等，对二维体系中因对称性破缺、界面效应等产生的新奇电荷、自旋性质开展研究，通过多物理场等手段，对磁性体系的磁学性质形成有效调控并发展相关信息存储技术，为开发新型高密度磁存储器件提供有价值的参考。