Two-dimensional Overdamped Fluctuations of the Soft Perovskite Lattice in CsPbBr3

July 1, 2021
Two-dimensional Overdamped Fluctuations of the Soft Perovskite Lattice in CsPbBr3
Diffuse scattering from CsPbBr3 reveals a network of rods arising from overdamped phonons. Comparison of simulation (K > 0, upper half of plots) and CNCS data (K < 0, lower half) in the cubic phase for energy transfers, -2 to 2 meV (left) and higher energy transfers 2 to 10 meV (right).

Scientific Achievement

Highly overdamped phonon modes are observed in CsPbBr3 extending across entire Brillouin zone edges, corresponding to correlated atomic motions in two-dimensional sheets.

Significance and Impact

The newly understood atomic motions directly impact electronic gap-edge states and hence the opto-electronic and thermal properties that are relevant for possible thermoelectric and photovoltaic applications of CsPbBr3 and related materials.

Research Details

  • X-ray diffuse scattering also shows rod-like diffuse scattering features at the zone boundaries.
  • ensity functional theory and ab initio molecular dynamics calculations corroborate the experimental observations.

“Two-dimensional overdamped fluctuations of the soft perovskite lattice in CsPbBr3,”
Tyson Lanigan-Atkins1,8, Xing He, Matthew Krogstad2, Daniel Pajerowski, Doug Abernathy, Guangyong N. M. N. Xu, Zhijun Xu Duck-Y. Chung, Mercouri Kanatzidis, Stephan Rosenkranz, Raymond Osborn and Olivier Delaire,
Nature Materials (2021).
DOI: https://doi.org/10.1038/s41563-021-00947-y