Optical Control of Adaptive Nanoscale Domain Networks

               The Paper of the Day describes how the researchers used in situ x-ray nanodiffraction imaging to study the evolution of nanoscale polar domain networks in (PbTiO3)n/(SrTiO3)n superlattices under repetitive ultrafast optical excitation. The superlattice system is poised at the verge of phase transitions, making it highly responsive to external stimuli like light. The researchers found that the nanoscale polar phases and their domain boundaries could be drastically reconfigured by tuning the optical dosage, including the creation of previously unobserved "vortex-like-xy" and "super-stripe" phases. Phase-field simulations revealed that the key factors governing the formation of these optically-induced phases were the accumulated charge carrier concentration and the transient lattice temperature. The ability to program the nanoscale domain networks with light holds promise for applications in light-based neuromorphic computing.