Suppressing The Ferroelectric Switching Barrier in Hybrid Improper Ferroelectrics

Integration of ferroelectric materials in novel technological applications requires low coercive field materials, and consequently, design strategies to reduce the ferroelectric switching barriers. In this first principles study, we show that biaxial strain, which has a strong e ect on the ferroelectric ground states, can also be used to tune the switching barrier of hybrid improper ferroelectric Ruddlesden-Popper oxides. We identify the region of the strain-tolerance factor phase diagram where this intrinsic barrier is suppressed, and show that it can be explained in relation to strain induced phase transitions to nonpolar phases.

There are two main parts in this work: 1. Strain-tolerance Ruddlesden-Popper perovskite oxides phase diagram. All the density-functional theory based relaxed crystal structures, used in the main text, are included. 2. Polarization switching paths of Ruddlesden-Popper perovskite oxides. We also include Python scripts that are used to analyse the energy, polarization and octahedral rotation angle of a specific crytal structure.