# Indirect but Efficient: Laser-Excited Electrons Can Drive Ultrafast Polarization Switching in Ferroelectric Materials

## TL;DR

This paper introduces a laser-based method for ultrafast and efficient switching of ferroelectric polarization in materials like BaTiO3, using charge redistribution and ionic forces induced by optical pulses, avoiding complex terahertz sources.

## Contribution

It proposes a novel laser-tuning mechanism for ferroelectric switching that is faster, more efficient, and compatible with existing laser technology.

## Key findings

- Achieved polarization switching within 200 fs in BaTiO3.
- Demonstrated charge redistribution reduces ferroelectric charge order.
- Reversible switching enabled with standard 800 nm laser pulses.

## Abstract

To enhance the efficiency of next-generation ferroelectric (FE) electronic devices, new techniques for controlling ferroelectric polarization switching are required. While most prior studies have attempted to induce polarization switching via the excitation of phonons, these experimental techniques required intricate and expensive terahertz sources and have not been completely successful. Here, we propose a new mechanism for rapidly and efficiently switching the FE polarization via laser-tuning of the underlying dynamical potential energy surface. Using time-dependent density functional calculations, we observe an ultrafast switching of the FE polarization in BaTiO3 within 200 fs. A laser pulse can induce a charge density redistribution that reduces the original FE charge order. This excitation results in both desirable and highly directional ionic forces that are always opposite to the original FE displacements. Our new mechanism enables the reversible switching of the FE polarization with optical pulses that can be produced from existing 800 nm experimental laser sources.