Semiconducting transition metal dichalcogenides (TMDs) have set a new paradigm for exploring atomic scale phenomena and future spin and valleytronic device applications. In this talk, I will present our recent investigations on TMDs, such as monolayers of WSe2, WS2, and MoTe2 using high-field magneto-optical spectroscopy. We use photoluminescence, photoluminescence excitation and reflectivity measurements to study the valley Zeeman splitting and valley polarization of neutral and charged excitons in these materials under magnetic fields up to 30 T at cryogenic temperatures [1-5]. While in MoTe2, the neutral A and B excitons as well as the charged A excitons show similar valley Zeeman splittings (g-factor ~ -4) , a more involved behavior is observed for singlet and triplet charged excitons in WS2 [3,4]. I will also present high-field Zeeman spectroscopy of single-photon emission in WSe2 . Our results shine light on the salient aspects of the spin- and valley-resolved band structure of TMDs.
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