发表机构
Universität Würzburg; Würzburg-Dresden Cluster of Excellence ctd.qmat, Universität Würzburg; Institut für Theoretische Physik und Astrophysik, Universität Würzburg; Physikalisches Institut, Universität Würzburg; Department of Physics and Astronomy, University of（维尔茨堡大学; 维尔茨堡-德累斯顿卓越集群 ctd.qmat; 维尔茨堡大学理论与天体物理研究所; 维尔茨堡大学物理研究所; 大学物理与天文学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
在SiC(0001)上单层Sb中实现最小二维双轨道kagome模型，通过轨道过滤和半填充驱动呼吸不稳定性及巨大带隙，并揭示轨道分辨的原子阻塞，为多轨道kagome物理提供基准平台。
AI 中文摘要
Kagome材料已成为关联和拓扑量子物质的主要平台，承载着源于受挫晶格几何的平带、狄拉克色散和范霍夫奇点。尽管其基本物理由典型的单轨道kagome模型所体现，但真实的kagome材料本质上是多轨道的，且通常化学和结构复杂，额外的三维耦合使得kagome几何和轨道自由度难以解耦。在此，我们在SiC(0001)上的单层Sb中实现了一个真正二维的元素双轨道kagome体系。衬底诱导的轨道过滤将面内Sb p_x/p_y轨道隔离成一个六带kagome流形，建立了一个化学简单、最小的多轨道kagome物理平台。我们展示了两个将该体系与典型单轨道模型区分开来的结果。第一，化学强制的半填充将费米能级钉扎在闭合节点线上，其有限的态密度驱动了保持单胞的呼吸不稳定性，并打开了巨大的绝缘带隙。第二，我们揭示了轨道分辨的原子阻塞：单个轨道衍生的流形实现了阻塞原子极限，而它们组合的半填充价带流形是非阻塞的。我们的结果确立了kagome锑烯作为在真正二维极限下探索轨道驱动的电子、结构和拓扑kagome物理的基准体系。
英文摘要
Kagome materials have emerged as a major platform for correlated and topological quantum matter, hosting flat bands, Dirac dispersions and van Hove singularities rooted in frustrated lattice geometry. While their essential physics is epitomized by the canonical single-orbital kagome model, real kagome materials are intrinsically multi-orbital and typically chemically and structurally complex, with additional three-dimensional coupling making kagome geometry and orbital degrees of freedom difficult to disentangle. Here we realize a truly two-dimensional, elemental two-orbital kagome system in monolayer Sb on SiC(0001). Substrate-induced orbital filtering isolates the in-plane Sb p_x/p_y orbitals into a six-band kagome manifold, establishing a chemically simple, minimal platform for multi-orbital kagome physics. We demonstrate two consequences that distinguish this system from the canonical single-orbital model. First, chemically enforced half filling pins the Fermi level to a closed nodal line, whose finite density of states drives a unit-cell-conserving breathing instability and opens a giant insulating gap. Second, we uncover orbital-resolved atomic obstruction: individual orbital-derived manifolds realize obstructed atomic limits, whereas their combined half-filled valence manifold is non-obstructed. Our results establish kagome antimonene as a benchmark system for exploring orbital-driven electronic, structural and topological kagome physics in the genuine two-dimensional limit.
