Polar topological superdomain arrays in PMN-PT crystals engineered via a voltage-free method

Domain engineering is an active field of research that aims to enhance the functional properties of ferroelectric materials for various applications. This work presents a voltage-free method for fabricating topological superdomain arrays in 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 (PMN-28PT) crystals. During the cooling process from high-temperature paraelectric phase to room temperature ferroelectric phase, the out-of-plane polarization of PMN-28PT crystals in contact with aluminum can be fully regulated downward, attributed to the difference in the work function of aluminum and PMN-28PT. In conjunction further with photolithography and ultraviolet light illumination, it is easy to obtain periodic strip domain structures with alternating up and down polarization. Moreover, this method can also control in-plane polarization, resulting in a large-scale central divergent/convergent topological superdomain array. These findings provide insights into ferroelectric domain engineering and have implications for the development of electromechanical, piezoelectronic, and photonic devices.