Noncentrosymmetric characteristics of defects on WTe2
Noncentrosymmetric characteristics of defects on WTe2
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WTe2 缺陷的非中心对称特征
DOI：
10.1103/physrevb.106.075428
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发表时间：
2022
影响因子：
3.7
通讯作者：
Lin Chun-Liang
中科院分区：
文献类型：
--
作者：
Chen Wan-Hsin;Kawakami Naoya;Lin Jhe-Jhih;Huang Hsiang-I;Arafune Ryuichi;Takagi Noriaki;Lin Chun-Liang
二碲化钨是一种过渡金属二硫属化物，具有新颖的电子结构和独特的性能，可应用于下一代器件。缺陷会以积极和消极的方式影响其属性。因此，迫切需要一个精确的分类，以帮助了解可能的影响。在这里，我们报告的缺陷的几何和电子特性的扫描隧道显微镜（STM）和密度泛函理论（DFT）计算相结合的识别。我们发现四种类型的缺陷来自一个失踪的Te原子，其中两个位于最上面的表面，而其他的表面下。前者是地形成像，并归因于表面Te原子的点空位。DFT计算揭示了缺陷周围原子的非中心对称位移，合理地再现了STM图像。有趣的是，后者的缺陷几乎没有观察到，但他们穿着非中心对称准粒子干涉（QPI）条纹，使我们能够识别它们。这些结果表明，STM-QPI可以是一种可行的方法来表征层状材料中的缺陷。
Tungsten ditellurideis a transition metal dichalcogenide with novel electronic structures and unique properties for application to next-generation devices. Defects incan impact its properties in both positive and negative ways. Therefore, it urgently requires a precise classification to help understand the possible impacts. Here we report on both geometric and electronic characteristics of the defects inidentified by the combination of scanning tunneling microscopy (STM) and density functional theory (DFT) calculation. We found four types of defects derived from a missing Te atom; two of them are located at the topmost surface while the others are under the surface. The former are imaged topographically and are ascribed to point vacancies of surface Te atoms. The DFT calculations reveal the noncentrosymmetric displacements of atoms around the defects and reasonably reproduce the STM images. Interestingly, the latter defects are hardly observed but they are dressed with the noncentrosymmetric quasiparticle interference (QPI) fringes which enable us to identify them. These findings demonstrate that STM-QPI can be a feasible method to characterize the defects in layered materials.