Real topography, atomic relaxations, and short-range chemical interactions in atomic force microscopy:: The case of the α-Sn/Si(111)-(√3x√3)R30° surface
Real topography, atomic relaxations, and short-range chemical interactions in atomic force microscopy:: The case of the α-Sn/Si(111)-(√3x√3)R30° surface
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DOI：
10.1103/physrevb.73.205329
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发表时间：
2006-05-01
影响因子：
3.7
通讯作者：
Abe, Masayuki
中科院分区：
文献类型：
--
作者：
Sugimoto, Yoshiaki;Pou, Pablo;Abe, Masayuki
利用原子力显微镜（AFM）和基于密度泛函理论的第一性原理计算研究了Sn/Si（111）-（root 3 × root 3）R30度表面在1/3 ML覆盖率下的室温相结构.通过调整在表面的Sn浓度，我们已经能够区分Sn和Si吸附原子，并确保AFM形貌为不同的阶段类似于使用扫描隧道显微镜报道的。在镶嵌和中间阶段，Si吸附原子的地形高度对周围Sn吸附原子的数量的依赖性已被确定。然而，在纯相，Sn吸附原子和替代Si缺陷，这是固有的AFM观察之间的测量高度差的变化，报告。可靠的室温力光谱测量使用原子跟踪技术和第一性原理计算提供了一个解释这些引人注目的诱导高度变化的纯相在两个不同的强度的短程化学相互作用和尖端诱导原子弛豫。我们的研究结果表明，真正的原子分辨率的AFM测量在低相互作用力和接近显着的短程化学相互作用的发病提供了直接访问异质半导体表面的真实的结构。
We have investigated the phases of the Sn/Si(111)-(root 3 x root 3)R30 degrees surface below 1/3 ML coverage at room temperature by means of atomic force microscopy (AFM) and density functional theory based first-principles calculations. By tuning the Sn concentration at the surface we have been able to discriminate between Sn and Si adatoms, and to assure that the AFM topography for the different phases resembles the one reported using scanning tunneling microscopy. In the mosaic and the intermediate phases, a dependence of the topographic height of the Si adatoms on the number of surrounding Sn adatoms has been identified. In the pure phase, however, variations in the measured height difference between the Sn adatoms and the substitutional Si defects, which are intrinsic to the AFM observation, are reported. Reliable room-temperature force spectroscopic measurements using the atom-tracking technique and first-principles calculations provide an explanation for these striking induced height variations on the pure phase in terms of both the different strength of the short-range chemical interaction and tip-induced atomic relaxations. Our results suggest that the corrugation measured with true atomic resolution AFM operated at low interaction forces and close to the onset of significant short-range chemical interactions provides direct access to the real structure of heterogeneous semiconductor surfaces.