Two-dimensional overdamped fluctuations of the soft perovskite lattice in CsPbBr3

T. Lanigan-Atkins, X. He, M. J. Krogstad, D. M. Pajerowski, D. L. Abernathy, Guangyong N.M.N. Xu, Zhijun Xu, D. Y. Chung, M. G. Kanatzidis, S. Rosenkranz, R. Osborn*, O. Delaire*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

69 Scopus citations


Lead halide perovskites exhibit structural instabilities and large atomic fluctuations thought to impact their optical and thermal properties, yet detailed structural and temporal correlations of their atomic motions remain poorly understood. Here, these correlations are resolved in CsPbBr3 crystals using momentum-resolved neutron and X-ray scattering measurements as a function of temperature, complemented with first-principles simulations. We uncover a striking network of diffuse scattering rods, arising from the liquid-like damping of low-energy Br-dominated phonons, reproduced in our simulations of the anharmonic phonon self-energy. These overdamped modes cover a continuum of wave vectors along the edges of the cubic Brillouin zone, corresponding to two-dimensional sheets of correlated rotations in real space, and could represent precursors to proposed two-dimensional polarons. Further, these motions directly impact the electronic gap edge states, linking soft anharmonic lattice dynamics and optoelectronic properties. These results provide insights into the highly unusual atomic dynamics of halide perovskites, relevant to further optimization of their optical and thermal properties.

Original languageEnglish (US)
Pages (from-to)977-983
Number of pages7
JournalNature materials
Issue number7
StatePublished - Jul 2021

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering
  • Chemistry(all)
  • Materials Science(all)


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