The surface of a three-dimensional topological insulator (TI) hosts two-dimensional massless Dirac fermions (DFs), the gapless and spin-helical nature of which leads to their high transmission through surface defects or potential barriers. Here, we report the behaviors of topological surface states (TSS) in a triangular quantum corral (TQC) which, unlike a circular corral, is supposed to be totally transparent for DFs. By real-space mapping of the electronic structure of TQCs, both the trapping and detrapping behaviors of the TSS are observed. The selection rules are found to be governed by the geometry and spin texture of the constant energy contour of TSS upon the strong hexagonal warping in Bisub2/subTesub3/sub. Our work indicates the extended nature of TSS and elucidates the selection rules of the trapping of TSS in the presence of a complicated surface state structure, giving insights into the effective engineering of DFs in TIs.
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机译：三维拓扑绝缘体（TI）的表面包含二维无质量的狄拉克费米子（DFs），其无间隙和自旋螺旋性质导致它们通过表面缺陷或势垒的高透射率。在这里，我们报告在三角量子畜栏（TQC）中的拓扑表面状态（TSS）的行为，该三角形量子畜栏与圆形畜栏不同，它对DF来说是完全透明的。通过对TQC的电子结构进行实空间映射，可以观察到TSS的俘获和去俘获行为。发现选择规则受Bi 2 Te 3 中强六角形翘曲时TSS恒定能量轮廓的几何形状和自旋纹理支配。我们的工作表明了TSS的扩展性质，并阐明了在存在复杂表面状态结构的情况下TSS捕集的选择规则，从而洞察了TI中DF的有效工程。
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