Berlin 2024 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 46: Focus Session: Ultrafast Processes in Organic Semiconductors and Perovskites II (joint session O/CPP)

CPP 46.2: Vortrag

Donnerstag, 21. März 2024, 15:30–15:45, MA 004

Nonlinear Pathways for Coherent Control of Lead Halide Perovskite Lattices — •Sebastian F. Maehrlein — Fritz Haber Institute of the Max Planck Society, Berlin

Lead halide perovskites (LHPs) constitute a vast and highly diverse library of emerging semiconductors. So far, to tailor their optoelectronic properties, the material science community mainly focused on changing the static design of the perovskite lattice by tuning the chemical composition or morphology. Meanwhile, the full potential for dynamic phonon-driven ultrafast material control, as successfully applied for oxide perovskites, has rarely been exploited.

I will present a summary of linear and nonlinear, phononic and photonic, excitation pathways to coherently control lattice vibrations with the help of intense THz fields. This comprehensive toolset not only allows to drive also non-IR active modes, but additionally unlocks phonon phase-sensitive lattice trajectory control. In prototype MAPbBr3 and CsPbBr3, we demonstrate coherent control of the octahedral twists [1], which act as structural order parameter and modulate the optical bandgap. Moving to more complex systems, we unveil counterintuitive lattice coherences in mixed 4-cation LHPs, proving the versatility of our method and providing active feedback to the design of novel energy materials.

We acknowledge fruitful collaborations with the groups of X.-Y. Zhu (Columbia U.), T. Kampfrath (FU Berlin), and S. Mathur (U. of Cologne).

[1] Frenzel et al., Sci. Adv.9, eadg3856 (2023)

Keywords: nonlinear THz spectroscopy; nonlinear phononics; lattice dynamics; lead halide perovskites; emerging semiconductors