Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 87: Plasmonics and Nanooptics: Light-Matter Interaction, Spectroscopy I

O 87.9: Talk

Thursday, March 20, 2025, 17:00–17:15, H4

Revealing the crystallization dynamics of phase-change materials in vicinity of metallic nanostructures with multiphysics simulations — •Luis Schüler^{1, 2}, Lukas Conrads², Sebastian Meyer², Yingfan Chen², Lina Jäckering², Matthias Wuttig², Thomas Taubner², and Dmitry Chigrin^{1, 2} — ¹DWI - Leibniz Institute for Interactive Materials, Aachen — ²I. Institute of Physics (IA), RWTH Aachen University, Aachen

Optical metasurfaces composed of metallic or dielectric scatterers (meta-atoms) promise a powerful way of tailoring light-matter interactions. Phase-change materials (PCMs) are prime candidates for non-volatile resonance tuning of metasurfaces based on a change in refractive index. Precise resonance control can be achieved by locally applying laser pulses to crystallize a PCM, modifying the dielectric surrounding of meta-atoms. However, the complex crystallization kinetics of PCMs in the vicinity of metallic meta-atoms have not been studied yet. Here, we investigate metallic dimer antennas on top of the PCM Ge₃Sb₂Te₆ and address these nanoantennas with laser pulses to crystallize the PCM below. Our study reveals inhomogeneous crystallization caused by the absorption and heat conduction of the metallic nanoantennas. A self-consistent multiphysics model, including electromagnetic, thermal, and phase-transition processes, is employed to simulate the crystallization and predict the resulting resonance shift of the antennas. This model enables the optimization of the laser parameters and the geometry of the meta-atoms to achieve an optimal resonance shift, thereby improving the efficiency of metasurfaces.

Keywords: phase-change materials; multiphysics simulations; metasurfaces; nanoantennas