Periodically-arrayed ferroelectric nanostructures induced by strain concentration in SrTiO3

Ferroelectric behavior in mechanically strained SrTiO3 nanoporous is investigated using phase-field models. We find, in the paraelectric nanoporous, periodically arrayed ferroelectric nano-region is formed due to strain concentration, namely, polarization vortices emerge around each pore. Each ferroelectric region expands and connects each other with increasing strain, and ferroelectric network is finally formed. Since these ferroelectric regions can be regarded as a periodically arrayed ferroelectric nanomaterial embedded in a paraelectric material, this result means that periodically arrayed ferroelectric nanostructure, which may lead to novel functionalities, can be tailored through mechanical load. In addition, we find that the variation of load changes the geometrical characteristics of the ferroelectric structure such as shape and direction. Our finding provides a new concept to engineer future ferroelectric nanodevices by giving a new role to mechanical load.