对称保护的拓扑极化子
近日，美国德克萨斯大学奥斯汀分校Feliciano Giustino团队研究了对称保护的拓扑极化子。相关论文于2026年1月22日发表在《美国科学院院刊》杂志上。
固体中的涌现准粒子，由于电荷、轨道、自旋与晶格自由度之间复杂的相互作用，常常展现出独特的拓扑性质。在这些准粒子中，极化子作为费米子与玻色子场相互作用的首个已知表现，占据着特殊地位。尽管极化子已被研究近一个世纪，这些准粒子是否以及为何会展现拓扑性质，仍是悬而未决的问题。
研究组建立了支配大极化子中极化纹理拓扑结构的普适对称性原理。通过群论分析，研究组在时间反演对称系统中识别出四类不同的极化纹理，并证明它们携带整数拓扑电荷。研究组利用第一性原理计算对每类代表性材料进行前沿模拟，验证了这一分类方法。针对这些材料，他们计算了极化子拓扑在黄昆漫散射中的特征信号，并提出了利用超快电子和X射线散射实验探测这些准粒子的方案。
附：英文原文
Title: Symmetry-protected topological polarons
Author: Luo, Kaifa, Lafuente-Bartolome, Jon, Giustino, Feliciano
Issue&Volume: 2026-1-22
Abstract: Emergent quasiparticles in solids often exhibit unique topological properties as a result of the complex interplay between charge, orbital, spin, and lattice degrees of freedom. Among these quasiparticles, the polaron occupies a special place as the first known manifestation of the interaction between a fermion and a boson field. While polarons have been investigated for almost a century, whether these quasiparticles exhibit topological properties and why remain open questions. Here, we establish the universal symmetry principles governing the topology of polar textures in large polarons. Using a group-theoretic analysis, we identify four distinct classes of polar textures in time-reversal-invariant systems, and we show that they carry integer topological charges. We validate this classification by performing state-of-the-art first-principles calculations of materials representative of each class. For these materials, we compute the fingerprints of polaron topology in Huang diffuse scattering and propose ultrafast electron and X-ray scattering experiments to detect these quasiparticles.
DOI: 10.1073/pnas.2514647123
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2514647123
