The atomic and electronic structures of pristine PdSe2 as well as various intrinsic vacancy defects in PdSe2 are studied comprehensively by combining scanning tunneling microscopy, spectroscopy, and density functional theory calculations. Other than the topmost Se atoms, sublayer Pd atoms and the intrinsic Pd and Se vacancy defects are identified. Both VSe and VPd defects induce defect states near the Fermi level. As a result, the vacancy defects can be negatively charged by a tip gating effect. At negative sample bias, the screened Coulomb interaction between the scanning tunneling microscopy (STM) tip and the charged vacancies creates a disk-like protrusion around the VPd and crater-like features around VSe. The magnification effect of the long-range charge localization at the charged defect site makes sublayer defects as deep as 1 nm visible even in STM images. This result proves that by gating the probe, scanning probe microscopy can be used as an easy tool for characterizing sublayer defects in a nondestructive way.

中文翻译：

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高度各向异性过渡金属硫族硫化物PdSe2中的缺陷。

结合扫描隧道显微镜，光谱学和密度泛函理论计算，对原始PdSe2的原子和电子结构以及PdSe2中各种固有的空位缺陷进行了综合研究。除了最顶部的Se原子之外，还可以识别子层Pd原子以及本征Pd和Se空位缺陷。VSe和VPd缺陷都会在费米能级附近诱发缺陷状态。结果，空缺缺陷可以通过尖端浇口效应带负电。在负样品偏压下，扫描隧道显微镜（STM）尖端与带电空位之间的筛选库仑相互作用会在VPd周围形成盘状突起，并在VSe周围产生类似坑状的特征。即使在STM图像中，带电缺陷位点处的远程电荷局部化的放大效应也使可见到1 nm深的子层缺陷。该结果证明，通过对探针进行选通，可以将扫描探针显微术用作以非破坏性方式表征亚层缺陷的简便工具。