Electrical topological defects induced by terahertz laser pulses

Abstract

Recent experimental evidence and theoretical simulations have shown that electrical polarization can be tuned and even deterministically controlled in ferroelectrics by applying laser pulses having a frequency that is higher than that of the main polarization (soft) mode. Here, by using ab initio computations, we further discover that such pulses can also create nontrivial topological polar phases in bulk ferroelectric materials. Such a phenomenon is found to originate from nonthermal quenching process in which the applied intense ultrashort laser pulse first squeezes the ferroelectric phase into a cubic-like paraelectric phase at a moderate temperature and then to a renucleation process akin to the Kibble-Zurek mechanism creating nontrivial topological polar defects in the bulk ferroelectric ground-state phase. Our work therefore presents a novel and optical mean of creating topological defects in ferroelectrics.