Ideal weak topological insulator and protected helical saddle points
Ideal weak topological insulator and protected helical saddle points
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DOI：
10.1103/physrevb.108.l201104
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发表时间：
2023-11-07
影响因子：
3.7
通讯作者：
Yi，Ming
中科院分区：
文献类型：
--
作者：
Oh，Ji Seop;Xu，Tianyi;Yi，Ming
我们报道了在准一维卤化铋中设计和观察到的理想弱拓扑绝缘体。通过角分辨光电子能谱，我们发现在（001）面上拓扑暗态的同时，在侧面上的拓扑表面态以两个各向异性偏置的狄拉克锥的形式存在。结果完全确定了一个独特的侧表面哈密顿量，从而确定了两对非退化螺旋鞍点。表面狄拉克和螺旋鞍点都在195毫电子伏的全球体带隙的事实表明，这个系统是一个拓扑多体物理学的肥沃土壤的潜力。
We report the design and observation of an ideal weak topological insulator in a quasi-one-dimensional bismuth halide,. Via angle-resolved photoemission spectroscopy, we identify thathosts topological surface states on theside surface in the form of two anisotropic-offset Dirac cones while topologically dark on the (001) top surface. The results fully determine a unique side-surface Hamiltonian and thereby identify two pairs of nondegenerate helical saddle points. The fact that both the surface Dirac and helical saddle points are in the global bulk band gap of 195 meV suggests the potential of this system to be a fertile ground for topological many-body physics.