Hierarchical Disorder in Moiré Exciton Photoluminescence Probed by Spectral-Descriptor Correlations

Katsunori Wakabayashi

doi:10.1103/jt25-c8fp

paper

Hierarchical Disorder in Moiré Exciton Photoluminescence Probed by Spectral-Descriptor Correlations

arXiv:2606.06780 · doi:10.1103/jt25-c8fp

Abstract

Hyperspectral photoluminescence (PL) 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 multi-scale 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, $ξ (E_{cent}) \geq ξ (E_{dom})$ , 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 inter-descriptor correlations, including the near-perfect anticorrelation $ρ_{S} (Δ E_{cd}, R_{HL}) \approx - 0.978$ , 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 MoSe $_{2}$ /WSe $_{2}$ 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.

arXiv comment31 pages, 11 figures

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