Identification of atomic disorders and their subsequent control has proven to be a key issue in predicting, understanding, and enhancing the properties of newly emerging topological insulator materials. Here, we demonstrate direct evidence of the cation antisites in single-crystal SnBi₂Te₄ nanoplates grown by chemical vapor deposition, through a combination of sub-ångström-resolution imaging, quantitative image simulations, and density functional theory calculations. The results of these combined techniques revealed a recognizable amount of cation antisites between Bi and Sn, and energetic calculations revealed that such cation antisites have a low formation energy. The impact of the cation antisites was also investigated by electronic structure calculations together with transport measurement. The topological surface properties of the nanoplates were further probed by angle-dependent magnetotransport, and from the results, we observed a two-dimensional weak antilocalization effect associated with surface carriers. Our approach provides a pathway to identify the antisite defects in ternary chalcogenides and the application potential of SnBi2Te4 nanostructures in next-generation electronic and spintronic devices.

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事实证明，识别原子异常及其后续控制是预测，理解和增强新兴的拓扑绝缘体材料的性能的关键问题。在这里，我们证明了单晶SnBi ₂ Te _4中阳离子抗位的直接证据。通过亚微米级分辨率成像，定量图像模拟和密度泛函理论计算的组合，通过化学气相沉积法生长的纳米板。这些组合技术的结果表明，Bi和Sn之间存在可识别量的阳离子反位点，而高能计算表明，这种阳离子反位点的形成能较低。阳离子抗位点的影响也通过电子结构计算和传输测量进行了研究。纳米板的拓扑表面特性通过角度依赖性磁传输进一步探测，并且从结果中，我们观察到了与表面载体相关的二维弱抗定位作用。

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