Abstract by Richard Hardy
Chemistry and Biochemistry
Modeling ultrafast reversal of the ferroelectric polarization in LiNbO3
Utilizing terahertz radiation to coherently reverse the ferroelectric polarization of a material on extremely short timescales has the potential to create ultrafast switches that could increase computing speeds by several orders of magnitude. An understanding of the interatomic potential energy surface of the material is key in designing effective excitation schemes that will yield the predictable structural change required for desired applications. Here we present first-principles calculations of the interatomic potential energy surface of the ferroelectric oxide LiNbO3, and model the dynamic response following strong terahertz excitation of crystal phonon modes. In contrast to other models which typically only account for coupling between two phonon modes, we consider coupling between all modes relevant to the polarization reversal, providing a more nuanced understanding of current experimental results, and allowing for exploration of previously unconsidered excitation pathways.