Regensburg 2025 – scientific programme

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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur

KFM 16: Perovskite and Photovoltaics II (joint session HL/KFM)

KFM 16.5: Talk

Thursday, March 20, 2025, 10:30–10:45, H13

THz-Driven Phonon Fingerprints of Hidden Symmetry Breaking in 2D Layered Hybrid Perovskites — •Joanna M. Urban¹, Michael S. Spencer¹, Maximilian Frenzel¹, Gaëlle Trippé- Allard², Marie Cherasse^1,3, Charlotte Berrezueta Palacios⁴, Olga Minakova¹, Luca Perfetti³, Stephanie Reich⁴, Martin Wolf¹, Emmanuelle Deleporte², and Sebastian F. Maehrlein^1,5,6 — ¹FHI Berlin — ²LuMIn, Université Paris-Saclay, ENS Paris-Saclay, CentraleSupélec, CNRS — ³LSI, CEA/DRF/IRAMIS, CNRS, École Polytechnique, Institut Polytechnique de Paris — ⁴FU Berlin — ⁵HZDR — ⁶TU Dresden

Metal halide perovskites (MHPs) are emerging as promising candidates for spintronic applications. In MHPs which lack inversion symmetry, strong spin-orbit coupling induces the Rashba-Dresselhaus effect, allowing spin current control. Here we use intense THz fields to coherently drive lattice dynamics in Ruddlesden-Popper 2D layered perovskites. We identify simultaneous IR and Raman activity of specific inorganic cage modes, suggesting the presence of inversion symmetry breaking despite the globally centrosymmetric crystal structure. By exploring the driving pathways of coherent phonons bearing the signatures of broken inversion symmetry, we lay the groundwork for simultaneous ultrafast control of optoelectronic and spintronic properties in 2D MHPs.

Keywords: Coherent phonons; THz-induced Kerr effect; 2D layered perovskites; Lattice dynamics; Inversion symmetry breaking