Chiral Phase Change Nanomaterials

ABSTRACT Active chiral nanomaterials are dynamic photonic materials offering unprecedented opportunities for high‐speed temporal control of chiral light‐matter interactions. However, demonstrating dynamic solid‐state chiral platforms remains challenging in the UV/VIS regime. By amalgamating the unique characteristics of geometric chirality and the non‐volatile phase change phenomena, chiral phase change nanomaterials hold great promise for energy‐efficient applications in reconfigurable optoelectronics, bio‐photonics, and information storage technologies. In this work, we reveal a bottom‐up, wafer‐scale fabrication technique for (GST) with a high degree of nanoscale control in three spatial dimensions, yielding densely packed phase change nanomaterials featuring 15 nm cross‐sectional diameters. We demonstrate tunable circular birefringence and dichorism, corroborated by a numerical model, explaining the origin of chiro‐optical effects observed in the material plasmonic regime. Furthermore, the GST nano‐helices exhibit over 50K reversible cycles using a repeated sequence of four 4 crystallization pulses and a singular 400 ns pulse for amorphization, enabling temporal manipulation of the chiro‐optical response maximally at 410 nm. Our work not only achieves the critical goal of wafer‐scale nano‐engineering of chiral chalcogenide phase change materials but also reversible optical actuation with low programming fluence, long cycling endurance, and fast switching.