Intensity-driven Mott-like transition in a 2D Ruddlesden-Popper perovskite
Abstract
Two-dimensional Ruddlesden-Popper-type halide perovskites have emerged as promising cutting-edge nonlinear optical materials due to their strong excitonic effects and carrier-density-dependent optical responses. In this work, we investigate the nonlinear optical properties and ultrafast carrier dynamics of (BA)2PbI4 under infrared excitation, resonant with the two-photon energy of its excitonic transition. Using a nonlinear femtosecond Z-scan measurement with a 1030\,nm pump pulse, we observe a pronounced intensity-dependent evolution of the nonlinear absorption coefficient and the refractive index. With increasing pump intensity, a switch from saturable absorption to reverse saturable absorption emerges, suggesting an intensity-driven Mott-like transition. To elucidate the underlying carrier dynamics, intensity-dependent transient absorption spectroscopy was performed under the same excitation intensities. This reveals a long-lived charge carrier population above the estimated Mott density, reflecting a clear phase transition from an exciton-dominated regime to a dense electron-hole plasma regime. Moreover, such an intensity-driven, high, and switchable nonlinear optical response, along with a Mott-like transition under infrared pulse excitation, makes the 2D (BA)2PbI4 perovskites suitable for all-optical operation in the infrared regime.
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BibTeX
@misc{mondal2026intensitydriven,
title = {{Intensity-driven Mott-like transition in a 2D Ruddlesden-Popper perovskite}},
author = {Koushik Mondal and Amit Haldar and Indrajit Mondal and Arpita Dutta and Himanshu Bhatt and Biswajit Mahata and Soumili Banerjee and Hirendra Nath Ghosh and Satyaprasad P Senanayak and Shovon Pal},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.30964},
eprint = {2610.30964},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.30964},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Intensity-driven Mott-like transition in a 2D Ruddlesden-Popper perovskite
AU - Koushik Mondal
AU - Amit Haldar
AU - Indrajit Mondal
AU - Arpita Dutta
AU - Himanshu Bhatt
AU - Biswajit Mahata
AU - Soumili Banerjee
AU - Hirendra Nath Ghosh
AU - Satyaprasad P Senanayak
AU - Shovon Pal
PY - 2026
DA - 2026/10/22
PB - arXiv
DO - 10.48550/arxiv.2610.30964
UR - https://arxiv.org/abs/2610.30964
AB - Two-dimensional Ruddlesden-Popper-type halide perovskites have emerged as promising cutting-edge nonlinear optical materials due to their strong excitonic effects and carrier-density-dependent optical responses. In this work, we investigate the nonlinear optical properties and ultrafast carrier dynamics of (BA)_2PbI_4 under infrared excitation, resonant with the two-photon energy of its excitonic transition. Using a nonlinear femtosecond Z-scan measurement with a 1030\,nm pump pulse, we observe a pronounced intensity-dependent evolution of the nonlinear absorption coefficient and the refractive index. With increasing pump intensity, a switch from saturable absorption to reverse saturable absorption emerges, suggesting an intensity-driven Mott-like transition. To elucidate the underlying carrier dynamics, intensity-dependent transient absorption spectroscopy was performed under the same excitation intensities. This reveals a long-lived charge carrier population above the estimated Mott density, reflecting a clear phase transition from an exciton-dominated regime to a dense electron-hole plasma regime. Moreover, such an intensity-driven, high, and switchable nonlinear optical response, along with a Mott-like transition under infrared pulse excitation, makes the 2D (BA)_2PbI_4 perovskites suitable for all-optical operation in the infrared regime.
ER -