{
  "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)$_2$PbI$_4$ 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)$_2$PbI$_4$ perovskites suitable for all-optical operation in the infrared regime.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2610.30964",
  "author_total": 10,
  "authors": [
    {
      "name": "Koushik Mondal"
    },
    {
      "name": "Amit Haldar"
    },
    {
      "name": "Indrajit Mondal"
    },
    {
      "name": "Arpita Dutta"
    },
    {
      "name": "Himanshu Bhatt"
    },
    {
      "name": "Biswajit Mahata"
    },
    {
      "name": "Soumili Banerjee"
    },
    {
      "name": "Hirendra Nath Ghosh"
    },
    {
      "name": "Satyaprasad P Senanayak"
    },
    {
      "name": "Shovon Pal"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9dhhd0d94nbpe.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2610.30964",
  "fulltext_url": null,
  "id": "9dhhd0d94nbpe",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2610.30964",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ],
    [
      "openalex",
      "2208|Perovskite Materials and Applications"
    ]
  ],
  "openalex": "W7223401213",
  "pdf_url": "https://arxiv.org/pdf/2610.30964",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-22",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9dhhd0d94nbpe.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:34:34Z",
      "native_id": "2610.30964",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2610.30964"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Intensity-driven Mott-like transition in a 2D Ruddlesden-Popper perovskite",
  "title_text": "Intensity-driven Mott-like transition in a 2D Ruddlesden-Popper perovskite",
  "type": "preprint",
  "updated_at": "2026-10-30T12:34:34Z",
  "url": "https://research.draconitic.com/paper/9dhhd0d94nbpe",
  "venue": "arXiv",
  "versions": []
}