Research: 

The potentially high data storage density of ferroelectric remanent storage devices is of great interest. Ferroelectrics under tetragonal strain have two polarization orientations with symmetrically equivalent ground states separated by an energy barrier, and polarization can be reversed under an electric field. Many experimental approaches are limited in thin-film regime and other theoretical work are based on relatively crude models. We try to raise the possibility of using this effect to "read" or "write" date storage media within 10 ps using a well validated atomic potential model of PbTiO₃ based on DFT calculations. We find that the coherent domain reorientation can be accomplished with a carefully timed and designed THz regime electric field. We got fruitful results from both 0 K and finite-temperautre studies. More finite-temperautre issues are currently under investigation.