Kasai Kohta, Xu Tao, Minami Susumu, Shimada Takahiro
Department of Mechanical Engineering and Science, Kyoto University, Nishikyo-ku, Kyoto 615-8540, Japan.
Nano Lett. 2024 Oct 23;24(42):13247-13254. doi: 10.1021/acs.nanolett.4c03406. Epub 2024 Oct 11.
Emerging polar skyrmion crystals (SkX) have raised much interest for technological applications owing to their nontrivial topologies of electric dipoles, quasiparticle-like behaviors, and unique electrical responses. Understanding SkX defects, especially dislocations, is crucial for their unique lattice dynamics and responses; however, it still remains elusive. Here, we have not only demonstrated that a SkX dislocation exhibits an anomalously deformed core structure with over 50% elongation of skyrmions but also discovered that Volterra's elasticity theory of dislocation is broken down in SkX. Our phase-field simulation reveals that these distinct features of SkX dislocation arise from a rigid to soft quasiparticle transition of skyrmions depending on the electric field and temperature. In SkX, there exist inherent mechanics that mitigate the mismatch by both migration and deformation of skyrmions. This work provides novel insights into a new class of lattice mechanics and related functionality arising from the unique properties of quasi-particle SkX.
新兴的极性斯格明子晶体（SkX）因其电偶极子的非平凡拓扑结构、类准粒子行为和独特的电响应而在技术应用方面引起了广泛关注。了解SkX缺陷，尤其是位错，对于其独特的晶格动力学和响应至关重要；然而，这仍然难以捉摸。在这里，我们不仅证明了SkX位错表现出异常变形的核心结构，斯格明子伸长超过50%，而且还发现Volterra位错弹性理论在SkX中失效。我们的相场模拟表明，SkX位错的这些独特特征源于斯格明子根据电场和温度从刚性到软准粒子的转变。在SkX中，存在通过斯格明子的迁移和变形来减轻失配的固有机制。这项工作为一类新的晶格力学以及由准粒子SkX的独特性质产生的相关功能提供了新的见解。
