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.
