Thermal triggering for multi-state switching of polar topologies

Particle-like topological structures such as polar skyrmions in ferroelectrics have the potential for application in high-density information storage. Since the polar topologies arise from a complicated competitive energy balance, such non-trivial topological states are difficult to manipulate by applying non-persistent external stimuli, such as bias or strain. Thus, a flexible strategy for manipulating topological polar states is needed to realize ultrahigh-density topological devices. Here we demonstrate that thermal excitation can simultaneously regulate the competition of elastic, electrostatic, polarization gradient and Landau energies to trigger polar topological state switching. By designing the temperature evolution pathways, the individual states that are believed to be unstable or intermediate can now be switched and stabilized. Therefore, our strategy expands the diversity of polar topologies in a single superlattice system. Furthermore, we demonstrate the laser-based thermal local switching of polar solitons ranging from several hundred nanometres to a few topologies. These findings will advance the design of polar topology-based ultrahigh-density storage.