Ultrafast acoustic phonon scattering in CH3NH3PbI3 revealed by femtosecond four-wave mixing

Samuel A March; Drew B Riley; Charlotte Clegg; Daniel Webber; Ian G Hill; Zhi-Gang Yu; Kimberley C Hall

doi:10.1063/1.5120385

Ultrafast acoustic phonon scattering in CH₃NH₃PbI₃ revealed by femtosecond four-wave mixing

J Chem Phys. 2019 Oct 14;151(14):144702. doi: 10.1063/1.5120385.

Authors

Samuel A March¹, Drew B Riley¹, Charlotte Clegg¹, Daniel Webber¹, Ian G Hill¹, Zhi-Gang Yu², Kimberley C Hall¹

Affiliations

¹ Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
² Washington State University, Spokane, Washington 99210, USA.

PMID: 31615224
DOI: 10.1063/1.5120385

Abstract

Carrier scattering processes are studied in CH₃NH₃PbI₃ using temperature-dependent four-wave mixing experiments. Our results indicate that scattering by ionized impurities limits the interband dephasing time (T₂) below 30 K, with strong electron-phonon scattering dominating at higher temperatures (with a time scale of 125 fs at 100 K). Our theoretical simulations provide quantitative agreement with the measured carrier scattering rate and show that the rate of acoustic phonon scattering is enhanced by strong spin-orbit coupling, which modifies the band-edge density of states. The Rashba coefficient extracted from fitting the experimental results (γ_c = 2 eV Å) is in agreement with calculations of the surface Rashba effect and recent experiments using the photogalvanic effect on thin films.