Abstract
Two-dimensional transition metal dichalcogenides (TMDs) hetero-layers have proven promising for future valleytronic, spintronic, and quantum computing applications owing to their ability to host real space-separated excitons with strong binding energy and long radiative lifetime. However, the full physical understanding of the energetics, excitation mechanisms, and dynamics of those special quasiparticles has not been reached yet. Moreover, the optimum heterolayer structures among the many alternatives for hosting the long-lived interlayer excitons have not been determined either experimentally or theoretically. Heterolayer TMD engineering is highly practical in that sense, as interlayer distance, stacking, the type of constituent TMD, and the electric field, all thoroughly affect the emergent excitonic properties. Moreover, its "two-faced" Janus TMD (JTMD) structures (high-quality fabrication has recently been achieved) possessing an intrinsic out-of-plane electric dipole find additional combinational opportunities towards even more versatile excitonic optimization.
Therefore, we propose a highly accurate ab initio computational framework to investigate the direct and indirect exciton spectrum of TMD/JTMD and TMD/TMD/JTMD (TMD = MoS2, MoSe2, WS2, WSe2; JTMD = MoSSe, WSSe) 2D heterostructures. We plan to computationally characterize exciton dynamics including phonon-mediated exciton excitation rates and identify the most promising heterolayer crystals, with unprecedented exciton lifetimes for applications in advanced optoelectronics and emergent quantum technology. The proposed computational framework will also contribute to current full ab initio modeling developments and pave the way for the fundamental understanding of interlayer excitons physics, along with creation and annihilation mechanisms.
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