Hierarchical disorder in moiré exciton photoluminescence probed by spectral-descriptor correlations

Katsunori Wakabayashi

doi:10.1103/jt25-c8fp

Journal article Hierarchical disorder in moiré exciton photoluminescence probed by spectral-descriptor correlations

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Katsunori Wakabayashi. Hierarchical disorder in moiré exciton photoluminescence probed by spectral-descriptor correlations. Physical Review Research. 2026, 8 (3), 033150. https://doi.org/10.1103/jt25-c8fp

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Hyperspectral photoluminescence maps of moiré transition-metal dichalcogenide heterobilayers encode rich information about the underlying disorder, but extracting it is hampered by the ambiguity of assigning individual spectral peaks. We show that the spatial correlations among a set of simple, peak-decomposition-free spectral descriptors—such as the centroid energy, the dominant-peak energy, and a sharp-line fraction—provide a peak-decomposition-free route to infer features of that disorder. Different descriptors act as filters that select different components of a multiscale disorder landscape—a smooth, micron-correlated background and a dense set of localized traps—and therefore acquire different spatial correlation lengths. The central prediction is a correlation-length hierarchy, 𝜉⁡(𝐸cent)≥𝜉⁡(𝐸dom), which we derive by splitting the dominant-peak energy into a smooth background part and a short-range trap-switching fluctuation. The same picture explains the measured interdescriptor correlations, including the near-perfect anticorrelation 𝜌S⁡(Δ⁢𝐸cd,𝑅HL)≈−0.978, which we show to be a robust geometric trend for spectra dominated by a common emission-envelope asymmetry. Benchmarked against phenomenological simulations, Hamiltonian diagonalization, and the measured MoSe2/WSe2 descriptor correlations, the framework turns descriptor maps into a quantitative, peak-decomposition-free probe of slow disorder and local traps in moiré excitons and, more broadly, in disordered semiconductor emitters.

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