Vanishing Polarizability of Dark Excitons in WSe2: Implications for Noise-Resilient Quantum States.

The spin-triplet dark excitons in transition metal dichalcogenides, such as WS2 and WSe2, are promising for quantum information processing due to their long lifetimes and robust spin-valley states. While effectively utilizing these states requires a precise understanding of their modulation by external controls, it remains less explored compared to the bright counterparts. Here, we investigate the out-of-plane electric field dependence of the neutral dark (D0) exciton in the dual-gated monolayer WSe2. Contrary to the large Stark shifts observed in interlayer excitons, we demonstrate that the D0 exciton exhibits a vanishingly small polarizability (<6.7 × 10-10 D·mV-1). We attribute this electrical immunity to strong spatial confinement. Crucially, we show that this insensitivity extends to the magnetic response, where the g-factor remains robust against electric field variations. Our results establish the dark exciton as a noise-resilient building block for future spin-valley quantum information processing.