Persistence of the topological surface states in Bi2Se3 against Ag intercalation at room temperature
Persistence of the topological surface states in Bi2Se3 against Ag intercalation at room temperature
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室温下 Bi2Se3 中 Ag 插层拓扑表面态的持久性
DOI：
10.1021/acs.jpcc.0c07462
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发表时间：
2020
期刊：
影响因子：
3.7
通讯作者：
Y. Ueda and A. Kimura
中科院分区：
文献类型：
--
作者：
M. Ye;K. Kuroda;M. Otrokov;A. Ryabishchenkova;A. Ernst;E. V. Chulkov;M. Nakatake;M. Arita;T. Okuda;T. Matsushita;L. T_th;H. Daimon;K. Shimada;Y. Ueda and A. Kimura
采用扫描隧道显微镜（STM）、光电子能谱（XPS）和第一性原理计算相结合的实验方法，研究了Ag原子沉积后拓扑绝缘体Bi2Se3的电子结构和原子结构.我们从STM的结果表明，沉积的Ag原子被稳定的表面下，而不是被吸附在最上面的表面。我们进一步从角分辨光电子能谱中揭示了Bi2Se3（0001）拓扑表面态在大量吸收Ag原子后保持不间断。对软X射线激发的Ag芯态光电子强度的分析表明，大量沉积的Ag原子向更深的地方扩散，超出了X射线光电子能谱的探测深度。第一性原理计算确定的八面体网站之间的货车德瓦耳斯间隙五层是最有利的位置的Ag原子的表面下，这产生了良好的协议之间的模拟和实验STM图像。这些发现为在不干扰拓扑非平凡表面态的情况下定制拓扑绝缘体的局域晶格结构提供了一种有效的方法。
The electronic and atomic structures of topological insulator Bi2Se3, upon Ag atom deposition, have been investigated by combined experimental methods of scanning tunneling microscopy (STM), photoelectron spectroscopy, and first-principles calculations. We show from the results of STM that the deposited Ag atoms are stabilized beneath the surface instead of being adsorbed on the topmost surface. We further reveal from the angle-resolved photoemission spectroscopy that the Bi2Se3(0001) topological surface states stay uninterrupted after a large amount of absorption of Ag atoms. Our analysis of the photoelectron intensity of Ag core states excited by soft X-ray suggests that a large amount of deposited Ag atoms diffused into a deeper place, which is beyond the probing depth of X-ray photoelectron spectroscopy. The first-principles calculations identify the octahedral site in the van der Waals gaps between quintuple layers to be the most favorable locations of Ag atoms beneath the surface, which yields good agreement between the simulated and experimental STM images. These findings pave an efficient way to tailor the local lattice structures of topological insulators without disturbing the topologically nontrivial surface states.