Title | Driving Lattice Dynamics in 2D Perovskites via THz Kerr Effect
Date | October 2, 2023
Abstract | Charge carrier-phonon interaction governs lead halide perovskite’s optoelectronic properties. Understanding the complex vibrational dynamics and microscopic coupling mechanisms is crucial for material design. The THz-induced Kerr effect spectroscopy (TKE) technique allows us to drive the crystal lattice using sub-picosecond THz electric field pulses and observe the ensuing dynamics by probing the transient changes of birefringence. Recently, in 3D MAPbBr3 at low temperature, we demonstrated coherent THz control of the octahedral twist modes, which potentially play an important role in dynamic charge carrier screening [1]. In this talk, I will introduce the technique and discuss our most recent studies on layered Ruddlesden-Popper HOIPs, which combine the intriguing properties originating from the soft, polar, and anharmonic lattice with confinement effects due to lowered dimensionality. In quasi-2D compounds, already at room temperature we observe long-lived coherent phonon oscillations in the 0.5–3 THz range [2]. We analyze the mode symmetry and possible driving mechanisms and compare samples of different dimensionality to infer the microscopic origin of the vibrations.
References
[1] M. Frenzel, M. Cherasse et al., Sci. Adv.9, eadg3856(2023) DOI:10.1126/sciadv.adg3856
[2] Z. Zhang et al., Sci. Adv.9, eadg4417(2023) DOI:10.1126/sciadv.adg4417
