近日，浙江大学的张泽及其研究团队取得一项新进展。他们实现了极性拓扑的多状态热触发切换。相关研究成果已于2025年1月8日在国际权威学术期刊《自然—物理学》上发表。

本文证明了热激发可以同时调节弹性能、静电能、极化梯度能和朗道能之间的竞争，从而触发极性拓扑状态切换。通过设计温度演变路径，现在可以切换并稳定那些原本被认为是不稳定或中间状态的个体状态。因此，该研究的策略拓展了单一超晶格系统中的极性拓扑多样性。

此外，研究人员还展示了基于激光的热局部切换技术，能够在几百纳米到几个拓扑结构的范围内切换极性孤子。这些发现将推动基于极性拓扑的超高密度存储设计的发展。

据悉，铁电体中的极性斯格明子等粒子状拓扑结构在高密度信息存储领域具有应用潜力。由于极性拓扑源自复杂的竞争能量平衡，因此这类非平凡拓扑状态难以通过施加非持久性外部刺激（如偏压或应变）来操纵。因此，需要一种灵活的策略来操纵拓扑极性状态，以实现超高密度拓扑器件。

附：英文原文

Title: Thermal triggering for multi-state switching of polar topologies

Author: Tong, Peiran, Zhou, Linming, Du, Kai, Zhang, Meng, Sun, Yuting, Sun, Tulai, Wu, Yongjun, Liu, Yong, Guo, Haizhong, Hong, Zijian, Xie, Yanwu, Tian, He, Zhang, Ze

Issue&Volume: 2025-01-08

Abstract: 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.

DOI: 10.1038/s41567-024-02729-0

Source: https://www.nature.com/articles/s41567-024-02729-0