Atomic dynamics and structure of the Ge(111)c(2 x 8) surface.
Atomic dynamics and structure of the Ge(111)c(2 x 8) surface.
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Ge(111)c(2 x 8) 表面的原子动力学和结构。
DOI：
10.1103/physrevb.51.10844
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Tosatti
中科院分区：
文献类型：
--
作者：
Takeuchi;Selloni;Tosatti
采用第一性原理分子动力学方法研究了Ge（111）c（2× 8）在T= 0和T= 300 K时的表面结构和原子动力学. T= 0基态结构显示了表面单胞中两个吸附原子和两个静止原子之间的不对称性，这在低能电子衍射实验中可以看到。这些不对称性，这是发现生存在T 300 K，导致区域折叠和分裂的表面声子模式。两对突出的表面模式被确定，主要是本地化的吸附原子和第二层原子下面。此外，在不同温度下的各层的均方位移的值指示相对于体积增强的表面非谐性。
We present results of a first-principles molecular-dynamics study of the surface structure and atomic dynamics of Ge (111) c (2× 8) at T= 0 and T= 300 K. The T= 0 ground-state structure shows asymmetries between the two adatoms and the two restatoms in the surface unit cell, which are seen experimentally in low-energy electron diffraction. These asymmetries, which are found to survive at T∼ 300 K, lead to zone folding and splitting of the surface phonon modes. Two pairs of prominent surface modes are identified, mostly localized on the adatoms and second-layer atoms just below. The values of the mean square displacements for the various layers at different temperatures moreover indicate an enhanced surface anharmonicity with respect to the bulk.