Intervalley polaronic biexcitons in metal halide perovskite quantum dots

Ajay K. Poonia, Megha Shrivastava, Wasim J. Mir, J. Aneesh, Angshuman Nag, K. V. Adarsh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations


The strong band edge exciton-phonon interactions in metal halide perovskite quantum dots (QDs) offer a unique platform to explore many-body phenomena. Employing CsPbBr3 QDs as a perovskite model system, we report the observation of spin-selective polaronic biexcitons using collective excitations of two circularly polarized ultrafast lasers of a duration that is two orders of magnitude shorter than the exciton lifetime and one order of magnitude shorter than the spin relaxation time. The intervalley polaron pairing of charge carriers determines the anomalously strong exciton-exciton interactions, where the Haynes factor is an order of magnitude larger than the bulk and five times larger than the two-dimensional and quantum well semiconductors, demonstrating a very robust correlation of excitons. Our findings reveal a mechanism of generating highly stable biexciton states even at room temperature to realize higher-order correlations of charge carriers such as quantum droplets and Bose-Einstein condensates.

Original languageEnglish (US)
Article numberA87
JournalPhysical Review B
Issue number16
StatePublished - Oct 15 2021

Bibliographical note

Funding Information:
The authors gratefully acknowledge the Science and Engineering Research Board (Project No. CRG/2019/002808), DAE BRNS (Sanction No. 37(3)/14/26/2016-BRNS/37245), and FIST Project for Department of Physics. The authors also gratefully acknowledge the support of Dr. Matthew C. Beard and Dr. Haipeng Lu of NREL. K.V.A. gratefully acknowledges support from a DST-IUSSTF BASE fellowship.

Publisher Copyright:
© 2021 American Physical Society.

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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