US Ireland Research and Development Partnership: Spin and valley interactions in intrinsic and magnetic two dimensional transition metal dichalcogenides for novel devices

二维过渡金属二硫属化物（2DMDs）是探索基本自旋和谷相互作用的理想平台，这些相互作用将形成自旋电子器件和谷电子器件的基础。在这个项目中，来自美国，爱尔兰共和国（ROI）和北方尔兰（NI）的研究人员建议研究基本特性，如相位和自旋相干性，谷间散射和本征和磁掺杂2D TMD中的磁性。 每个PI将通过美国爱尔兰研发合作伙伴计划得到各自资助机构的支持。 研究团队是跨学科的，具有互补的专业知识。 NI小组将使用最先进的理论方法进行多尺度建模，以预测新的特性，并提供对实验工作的基本理解。 ROI小组将提供多尺度表征，并开发新的扫描透射电子显微镜方法，以同时获得有关原子和磁性结构的信息。 美国研究小组将研究新的合成方法，以获得磁性2D材料，并进行量子传输测量，以阐明基本的自旋和谷间散射机制。 合作研究将通过组建一个跨学科团队来实现协同效应，该团队将致力于2D材料中的自旋和谷物理学，以实现令人兴奋的科学发现。 拟议项目的教育和培训活动将补充拟议项目的科学影响。 来自美国，爱尔兰和北方爱尔兰的研究生将受益于该计划的科学和教育部分。 这种合作将导致发展高度参与，全球网络的研究生，在国际和国家实验室环境中经验丰富的跨学科知识。 学生将通过发展超出其核心博士论文主题的专业知识的新技能，从国际交流中受益。 此外，重点推广活动将涉及高中学生以及初中和高中教师熟悉材料科学，并通过组织实验室参观，设计动手演示图尔斯和及时发布新闻稿来吸引公众。该提案的主要目标是提供以下方面的新见解：（一）极稀磁介质中自旋和谷与磁性杂质的基本相互作用（即内禀）或弱磁有序区;（ii）二维半导体在高磁有序区的铁磁性及其对自旋极化和相干性的影响。 从这个项目中获得的新知识将在实现基于2D TMD的未来自旋电子学和谷电子学器件方面起到补充作用。 此外，电掺杂仍然是二维半导体中一个尚未解决的问题，预计这项研究的结果将解决有关热力学浓度限制和杂质对电子和磁性影响的关键基本问题。 这些性质将通过量子输运和霍尔效应测量来研究，以获得关于非磁性材料的弱局域化的信息。 磁性样品中自旋极化输运的信息将通过面内磁场的磁阻测量获得。 预计这项研究将产生新的基础知识的基础，并探讨实验实现2D磁性TMD的自旋电子和谷电子器件的制造的可行性。 美国和爱尔兰的合作伙伴关系将提供一个理论和实验合作框架，以实现新的2D材料特性及其在设备应用中的潜在协同作用。

Two dimensional transition metal dichalcogenides (2D TMDs) are the ideal platform for exploration of fundamental spin and valley interactions that will form the foundation of spintronic and valleytronic devices. In this project, researchers from the United States, Republic of Ireland (ROI), and Northern Ireland (NI) propose to study fundamental properties, such as phase and spin coherences, inter-valley scattering, and magnetism in intrinsic and magnetically doped 2D TMDs. Each PI will be supported by their respective funding agencies through the US Ireland R & D Partnership Program. The Research Team is interdisciplinary with complementary expertise. The NI group will carry out multi-scale modeling using state-of-the-art theoretical methods to predict new properties as well as provide fundamental understanding of the experimental work. The ROI group will provide multi-scale characterization and develop new scanning transmission electron microscopy methods to simultaneously obtain information about atomic and magnetic structures. The US group will investigate new synthesis methods to obtain magnetic 2D materials and perform quantum transport measurements to elucidate fundamental spin and inter-valley scattering mechanisms. The collaborative research will lead to realization of synergies through formation of an interdisciplinary team who will work on spin and valley physics in 2D materials to enable exciting scientific discoveries. The educational and training activities of the proposed project will complement the scientific impact of the proposed project. The graduate students from the US, Ireland, and Northern Ireland will benefit from the scientific and educational components of the program. This collaboration will result in developing highly engaged, globally networked graduate students with interdisciplinary knowledge experienced in international and national laboratory environments. The students will benefit from international exchanges by developing new skills beyond the expertise of their core doctoral thesis topics. Additionally, focused outreach activities will involve engaging high school students as well as middle and high school teachers to be familiarized with materials science as well as engaging public by organizing laboratory tours, designing hands-on demonstrations, and issuing timely press releases.The main goal of this proposal is to provide new insights in: (i) fundamental interactions of spin and valley with magnetic impurities in the very dilute (i.e. intrinsic) or weak magnetic ordering regime; and (ii) ferromagnetism in 2D semiconductors in the high magnetic ordering regime and its influence on spin polarization and coherence. The new knowledge obtained from this project will be complementary in realizing future spintronics and valleytronics devices based on 2D TMDs. In addition, electrical doping remains an unresolved question in 2D semiconductors and it is expected the outcome of this research will address key fundamental questions regarding thermodynamic concentration limit and influence of impurities on electronic and magnetic properties. These properties will be investigated by quantum transport and Hall Effect measurements to obtain information about weak localization for the non-magnetic materials. Information about spin-polarized transport in magnetic samples will be obtained using magneto-resistance measurements with in-plane magnetic fields. It is expected that the research will generate the foundation of new fundamental knowledge and investigate the feasibility of experimentally realizing 2D magnetic TMDs for fabrication of spintronic and valleytronic devices. This US-Ireland partnership will provide a framework to collaborate theoretically and experimentally for realizing new 2D materials properties and thier potential synergies for device applications.