Coherent X-ray insights into topological polar structures under light illumination.

Numerous electronic devices have been designed using topological structures of spontaneous polarization, which have being studied for their intriguing physics^1,2. The key to understanding the local topological structure at the nanoscale scale in ferroelectric materials is the quantitative characterization of strain at the nanoscale³. We demonstrate in-situ X-ray Bragg coherent diffractive imaging of local strains in quasi-2D ferroelectric materials subjected to optical light illumination. In the presentation we shall address the observed light-induced changes in local strain and control of polar structures as interpreted by X-ray BCDI. This study lays the groundwork to understanding the role of lattice dynamics and polar structures in all-optical manipulation of ferroelectrics.