Possible experimental realization of a basic Z2 topological semimetal in GaGeTe
Possible experimental realization of a basic Z2 topological semimetal in GaGeTe
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DOI：
10.1063/1.5124563
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发表时间：
2019-12-01
期刊：
影响因子：
6.1
通讯作者：
Borisenko, Sergey
中科院分区：
文献类型：
--
作者：
Haubold, Erik;Fedorov, Alexander;Borisenko, Sergey
我们报道了实验和理论证据，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：体源电子和空穴以及表面态电子。这种电子情况在性质上类似于经典的3D拓扑绝缘体Bi2Se3，但重要的差异解释了GaGeTe史无前例的输运场景。高分辨角度分辨光电子能谱结合先进的能带结构计算表明，在GaGeTe布里渊区的T点上，由于特殊的能带反转，产生了一个很小的间接能隙。价带和导带的能量重叠将电子和类空穴载流子带入费米能级，而相应色散之间的动量差保持有限。我们认为，GaGeTe电子光谱的特性对拓扑物质的物理具有重要意义，并可能增强该材料的应用潜力。
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 classic 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 at the T-point of the Brillouin zone in GaGeTe. An energy overlap of the valence and conduction bands brings both electron and holelike 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.