标题： 可能的Z2拓扑半金属的基本实验实现 显示英文标题

标题： Possible Experimental Realization of a Basic Z2 Topological Semimetal

摘要： 我们报告了实验和理论证据，表明GaGeTe是一种基本的$Z_2$拓扑半金属，具有三种类型的电荷载流子：体起源的电子和空穴以及表面态电子。 这种电子情况在定性上类似于初始的三维拓扑绝缘体Bi2Se3，但重要的差异导致GaGeTe中出现前所未有的输运情景。 高分辨率角分辨光电子能谱结合先进的能带结构计算显示，GaGeTe在布里渊区的\textit{T}点由于特殊的能带反转导致了一个小的间接能隙。 价带和导带的能量重叠使得电子和空穴类载流子都到达费米能级，而相应色散之间的动量间隙仍然有限。 我们认为GaGeTe的电子谱特性对于拓扑物质的物理具有根本的重要性，并可能提升该材料的应用潜力。 显示英文摘要

摘要： We report experimental and theoretical evidence that GaGeTe is a basic $Z_2$ topological semimetal with three types of charge carriers: bulk-originated electrons and holes as well as surface state electrons. This electronic situation is qualitatively similar to the primer 3D topological insulator Bi2Se3, but important differences account for an unprecedented transport scenario in GaGeTe. High-resolution angle-resolved photoemission spectroscopy combined with advanced band structure calculations show a small indirect energy gap caused by a peculiar band inversion in the \textit{T}-point of the Brillouin zone in GaGeTe. An energy overlap of the valence and conduction bands brings both electron- and hole-like carriers to the Fermi level, while the momentum gap between the corresponding dispersions remains finite. We argue that peculiarities of the electronic spectrum of GaGeTe have a fundamental importance for the physics of topological matter and may boost the material's application potential.