Abstract
We elucidate the nature of the electron-phonon interaction in the archetypal hybrid perovskite using ab initio many-body calculations and an exactly solvable model. We demonstrate that electrons and holes near the band edges primarily interact with three distinct groups of longitudinal-optical vibrations, in order of importance: the stretching of the Pb—I bond, the bending of the Pb—I—Pb bonds, and the libration of the organic cations. These polar phonons induce ultrafast intraband carrier relaxation over timescales of 6–30 fs and yield polaron effective masses 28% heavier than the bare band masses. These findings allow us to rationalize previous experimental observations and provide a key to understanding carrier dynamics in halide perovskites.
- Received 12 February 2018
DOI:https://doi.org/10.1103/PhysRevLett.121.086402
© 2018 American Physical Society