FEAST - FerroElectricity using Ab-initio Simulations in the Time domain

• Applicant: Professorin Sangeeta Sharma, Ph.D.
• Subject Area: Theoretical Condensed Matter Physics
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 531202602

Controlling the dipole moment of ferroelectrics by external fields represents both a challenge of fundamental physics as well as a key requirement underpinning possible ferroelectric random access memory devices. The ultimate temporal limit at which matter can be manipulated is given by the time scales of lightwave induced optical excitations, of the order of attoseconds to a few femtoseconds. While for magnetic order a rich field has arisen in which control by ultrafast light pulses of magnetic order is now well established, a corresponding systematic effort exploring the ultrafast control of ferroelectrics remains in its infancy. In this project we will apply the tools of time dependent density functional theory (TDDFT) to the dynamics of the electric charge and current in ferroelectric materials in order to understand and predict their behavior on femtosecond timescales. This first principles approach -- free of any fitting parameters -- has proven to be profoundly useful in unveiling ultrafast phenomena in the field of femtomagnetism, and we will here employ TD-DFT to both address fundamental questions, such as how transient current signals can be employed to infer the temporal evolution in dipole order, as well as to systematically explore the physics of ultrafast ferrolectricity in a range of materials from bulk ferroelectrics, such as the distorted Perovskites, to the rapidly emerging field of $2$D materials. The proposal is therefore expected to advance both understanding of the fundamental physics of ultrafast ferroelectricity, as well as its practical application in key dielectric materials.

• DFG Programme: Research Grants