2025/07/15 by Josep Planelles, Juan I. Climente, Planelles, Josep +3
Engineering · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Molecular Junctions and Nanostructures
paper · pdf · doi:10.48550/arxiv.2507.11087
openalex publication_date 2025/07/15 · openalex created_date 2025/10/08 · openalex updated_date 2026/07/28
Recent experimental and computational studies suggest that biexcitons (BX) confined in large CsPbBr3 nanocrystals experience reduced dielectric screening as compared to excitons (X) and trions (X^*). Here we provide a physical rationale to explain such a behavior. A characteristic frequency is introduced, which describes the internal dynamics of an exciton within the excitonic complex. By means of effective mass--variational Quantum Monte Carlo simulations, we show that, in large nanocrystals, the frequency is similar for X and X^*, but smaller for BX. Because the frequencies exceed that of the bulk longitudinal optical phonon, this leads to a reduced dielectric constant for BX, which is in contrast with the behavior of strongly confined nanocrystals.