Nonlinear THz Control of the Lead Halide Perovskite Lattice

TL;DR

This study demonstrates the use of intense THz electric fields to directly control lattice vibrations in lead halide perovskites, enabling ultrafast manipulation of their structural and electronic properties for advanced optoelectronic applications.

Contribution

It introduces a novel method of nonlinear THz excitation to control phonon modes in lead halide perovskites, revealing dynamic lattice control beyond chemical tuning.

Findings

Coherent octahedral twist modes are excited at 0.9 - 1.3 THz.

THz-induced Kerr effect is governed by Raman-active phonons.

Potential for controlling phase transitions and dynamic disorder.

Abstract

Lead halide perovskites (LHPs) have emerged as an excellent class of semiconductors for next-generation solar cells and optoelectronic devices. Tailoring physical properties by fine-tuning the lattice structures has been explored in these materials by chemical composition or morphology. Nevertheless, its dynamic counterpart, phonon-driven ultrafast material control, as contemporarily harnessed for oxide perovskites, has not been established yet. Here we employ intense THz electric fields to obtain direct lattice control via nonlinear excitation of coherent octahedral twist modes in hybrid CH3NH3PbBr3 and all-inorganic CsPbBr3 perovskites. These Raman-active phonons at 0.9 - 1.3 THz are found to govern the ultrafast THz-induced Kerr effect in the low-temperature orthorhombic phase and thus dominate the phonon-modulated polarizability with potential implications for dynamic charge carrier screening beyond the Froehlich polaron. Our work opens the door to selective control of LHP's vibrational degrees of freedom governing phase transitions and dynamic disorder.