Magnetic brightening and its dynamics of defect-localized exciton emission in monolayer two-dimensional semiconductor.

Xiang, Yubei; Shinokita, Keisuke; Watanabe, Kenji; Taniguchi, Takashi; Matsuda, Kazunari · Sci Adv · 2025

basic_science · Level V

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Abstract

Quantum light sources, especially single-photon emitters, are crucial for advancing quantum technologies. Despite extensive research, the behavior of defect-localized excitons in monolayer WSe<sub>2</sub> under external perturbations, such as magnetic fields, remain underexplored. This study investigates the nature and dynamics of defect-localized excitons under in-plane magnetic fields using steady-state and time-resolved photoluminescence (PL) spectroscopy. Observations reveal a sharp PL peak, indicative of single-photon emission, with doublet peaks from hybridized spin-state excitons. Notably, magnetic brightening of the PL peak was detected at a low magnetic field (<1 tesla), and the dynamics of hybridized-state excitons under magnetic fields indicated field-induced state mixing, explaining the magnetic brightening. These findings advance tunable single-photon emitters controlled by magnetic fields, with implications for quantum optics applications.