Giant photoinduced chirality in thin film Ge₂Sb₂Te₅

Induction, tuning or amplification of chirality in various classes of materials and probing their chiral response is a subject of growing research. Here, we report a large chiral signal that is rapidly imprinted in achiral amorphous Ge2Sb2Te5 (GST) thin films measured using synchrotron circular dichroism spectroscopy. The chirality is induced by illuminating the films with pulsed circularly polarized (chiral) laser light for less than 2 microseconds in total. The effects of laser fluence and film thickness on the chiral response are reported. Correlation of the optical results with structural studies by electron diffraction and model simulations suggests that alignment of re‐amorphized fragments in the crystallized film along the electric field vector of the light forms the centers that are responsible for the observed chirality. These results suggest opportunities for practical applications of this phenomenon and provide avenues for further studies of chirality induction in materials with impact in a wide range of disciplines