发表机构
Goethe-Universität Frankfurt; University of Bristol; Argonne National Laboratory（法兰克福歌德大学; 布里斯托大学; 阿贡国家实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
研究以无杂质 kagome 磁体 quetzalcoatlite 为对象，通过从头算揭示其由层内与层间交换耦合竞争形成的三维手性磁态，该材料接近竞争磁 regime，或可通过调控实现量子自旋液体态。
AI 中文摘要
天然矿物 quetzalcoatlite Zn₆Cu₃(TeO₆)₂(OH)₆·(AgₓPbᵧClₓ₊₂ᵧ)是结构理想的 kagome 磁体，为在无杂质框架中探索几何阻挫、手性与可调性的相互作用提供平台。本文首次对其电子与磁学性质开展全面的从头算研究。电子结构以局域的半充满 Cu dₓ²₋ᵧ² 轨道为主，这些轨道因电子关联而成为绝缘态。将低能物理映射到海森堡模型后发现，磁性主要由两种交换相互作用调控：近邻层内 kagome 耦合与次近邻层间耦合，二者的竞争稳定了非传统的三维手性磁态。每个 kagome 层呈现√3×√3 有序，相邻层旋转 60°，沿晶体学 c 轴形成右手螺旋。这种本征手性序由晶体结构与磁相互作用自然产生，确立了 quetzalcoatlite 是完美 kagome 晶格上手性磁性的独特实现。同时，交换相互作用的小能量尺度使该材料接近竞争磁 regime，表明适度压力、化学取代或结构修饰可能显著增强阻挫、抑制长程有序，并潜在驱动系统进入量子自旋液体态。
英文摘要
The natural mineral quetzalcoatlite Zn$_6$Cu$_3$(TeO$_6$)$_2$(OH)$_6$ $\cdot$ (Ag$_x$Pb$_y$Cl$_{x+2y}$) is a structurally ideal kagome magnet, providing a platform for exploring the interplay of geometric frustration, chirality, and tunability in a disorder-free framework. Here, we present the (first) comprehensive ab initio study of its electronic and magnetic properties. The electronic structure is dominated by localized half-filled Cu $d_{x^2-y^2}$ orbitals that become insulating through electronic correlations. Mapping the low-energy physics onto a Heisenberg model reveals that the magnetism is governed primarily by two exchange interactions: a nearest-neighbor intralayer kagome coupling and a next-nearest-neighbor interlayer coupling. Their competition stabilizes an unconventional three-dimensional chiral magnetic state. Each kagome layer hosts a $\sqrt{3}\times\sqrt{3}$ order, while adjacent layers are rotated by $60^\circ$, producing a right-handed spiral along the crystallographic $c$-axis. This intrinsic chiral order emerges naturally from the crystal structure and magnetic interactions, establishing quetzalcoatlite as a distinctive realization of chiral magnetism on a perfect kagome lattice. At the same time, the small energy scale of the exchange interactions places the material close to competing magnetic regimes, suggesting that moderate pressure, chemical substitution, or structural modifications may strongly enhance frustration, suppress long-range order, and potentially drive the system toward a quantum spin-liquid state.
Comments9 Pages, including 6 Figures, and additional four pages of Supplementary Information
