Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 106, Taiwan, Republic of China.
J Chem Phys. 2009 Dec 14;131(22):224705. doi: 10.1063/1.3268776.
The atomic structure of the Ag/Ge(111)-(sq.rt.(3) x sq.rt.(3))R30 degrees surface is studied by scanning tunneling microscopy (STM) and the density functional theory (DFT) calculations. Our STM images have shown a structure which is different from the widely accepted honeycomb-chained-triangle (HCT) model before. The structure is similar to the inequivalent triangle (IET) model found for the Ag/Si(111)-(sq.rt.(3) x sq.rt(3))R30 degrees surface. This model proposed two types of silver triangles with different sizes in the unit cell, corresponding to the bright spots and the dark spots in the STM image. A distinguishable hexagonal pattern of the IET structure was well disclosed in the temperature range from 100 to 473 K in our STM studies for Ag/Ge(111)-(sq.rt.(3) x sq.rt.(3))R30 degrees. Furthermore, the result of the DFT calculations showed that the IET structure is 0.20 eV energetically more stable than the HCT model. Besides, the Ge triangles, which were not disclosed in earlier STM research, are found in this study.
通过扫描隧道显微镜（STM）和密度泛函理论（DFT）计算，研究了 Ag/Ge(111)-(sq.rt.(3) x sq.rt.(3))R30 度表面的原子结构。我们的 STM 图像显示的结构与之前广泛接受的蜂窝链三角形（HCT）模型不同。该结构类似于在 Ag/Si(111)-(sq.rt.(3) x sq.rt(3))R30 度表面发现的不等价三角形（IET）模型。该模型在单位晶胞中提出了两种具有不同大小的银三角形，分别对应于 STM 图像中的亮点和暗点。在我们对 Ag/Ge(111)-(sq.rt.(3) x sq.rt.(3))R30 度的 STM 研究中，在 100 到 473 K 的温度范围内，IET 结构的可分辨六边形图案得到了很好的揭示。此外，DFT 计算的结果表明，IET 结构在能量上比 HCT 模型稳定 0.20 eV。此外，在这项研究中发现了在早期 STM 研究中未揭示的 Ge 三角形。
