PtBi₂的外尔节点和费米弧的最小模型
A minimal model for the Weyl nodes and Fermi arcs of PtBi$_2$
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中文总结 AI 辅助
研究PtBi₂的外尔节点和费米弧，基于密度泛函理论计算，受晶体和时间反演对称性约束开发最小模型，能捕捉外尔节点演化及描述费米弧自旋动量锁定，再现其轨道内容和能带拓扑，为后续研究奠基。
中文摘要 AI 辅助
外尔半金属在其表面具有受拓扑保护的费米弧，源于体相外尔节点的陈数。在三角晶格的PtBi₂中，超导特征与费米弧相关。此前对这种表面超导性的理论描述依赖于与材料微观电子结构无直接关联的有效模型。本工作基于密度泛函理论计算并受相关晶体和时间反演对称性完全约束，开发了低能能带的最小描述。该模型捕捉了外尔节点随自旋轨道耦合的演化，包括节点湮灭，能描述表面费米弧的自旋动量锁定，再现了PtBi₂的轨道内容和能带拓扑，为进一步研究提供了起点。
英文摘要
Weyl semimetals host topologically protected Fermi arcs on their surfaces, originating from the Chern number of the bulk Weyl nodes. In trigonal PtBi$_2$, superconducting signatures have been associated with the Fermi arcs. Theoretical descriptions of this surface superconductivity have so far relied on effective models that are not directly tied to the microscopic electronic structure of the material. In this work we develop a minimal description of the low-energy bands guided by density functional theory calculations and fully constrained by the relevant crystalline and time-reversal symmetries. The model captures the evolution of the Weyl nodes with spin-orbit coupling, including node annihilations, and is able to describe the spin-momentum locking of the surface Fermi arcs. It reproduces the orbital content and the band topology of PtBi$_2$ and provides a starting point for further studies.
