Executive Summary : | The research in two-dimensional layered materials (2DLM) is expanding due to their unique optoelectronic properties, which are promising for nanoscale electronic and spintronic devices. Van der Waals (vdW) heterostructures of 2DLM show emerging properties, particularly in transition-metal dichalcogenides (TMD) of the form MX₂. These materials are interesting due to their enhanced spin-orbit interaction and unique spin-valley coupling. The project aims to explore spin and valley properties in various 2DLM and vdW heterostructures using the polarization degree of freedom of light. The project will involve adding polarization components and magnetic fields to existing setups for temperature-dependent photoluminescence (PL), picosecond excitation correlation (PEC) PL, and pump-probe differential reflectivity (PPDR) measurements. Hanle effect measurements and time-resolved magneto-optical Kerr effect (TR-MOKE) spectroscopy will be developed to estimate spin relaxation time and provide a direct time-domain depiction of spin precession and spin relaxation. The project will also study carrier dynamics, delay-dependent decay patterns, coherent and incoherent dynamics, spin relaxation processes, and spin-valley coupling effects in TMD samples. First-principle computational studies will be used to understand the results and predict materials' compositions for desired properties. Emerging properties in vdW heterostructures of TMD/graphene and TMD/TMD will be investigated. Upon completion, functional setups for the Hanle effect and TR-MOKE measurements will be developed, and physics questions will be clarified. These setups can be used for future studies of spin dynamics in other materials of interest, such as magnetic 2DLM, topological materials, and gate-controlled devices. |