Self-organization in Pd/W(110): interplay between surface structure and stress
Self-organization in Pd/W(110): interplay between surface structure and stress
复制标题
Pd/W(110) 中的自组织：表面结构与应力之间的相互作用
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
N. Binggeli
中科院分区：
文献类型：
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作者：
N. Stojić;T. Menteş;N. Binggeli
最近的研究表明，在高温下，W(110)上的亚单分子层Pd可以形成高度有序的线状介观条纹。这些条纹沿垂直于条纹周期的方向显示出具有纳米尺度周期性的内部Pd超结构。在低于条带形成温度的大范围温度范围内，也可以观察到相同类型的超结构。我们对W(110)面上Pd的这种超结构进行了理论和实验相结合的研究，并研究了它对线状介观条纹的影响。通过低能电子衍射和低能电子显微镜，我们发现它对温度和覆盖度的依赖比常规表面重建的预期要特殊得多。利用密度泛函理论，我们将Pd超结构模拟为周期空位线型组态，并研究了它们的能量学和弹性性质。根据我们计算的空位线组态的表面应力和各向异性，并基于连续介质弹性理论，我们定量地论证了空位线结构是形成线性介观条纹的先决条件。此外，我们还表明，驱动内部超结构形成的物理机制与形成介观条纹本身的物理机制非常相似。
It has recently been shown that submonolayer Pd on W(110) forms highly ordered linear mesoscopic stripes at high temperatures. The stripes display an internal Pd superstructure with a nano-scale periodicity along the direction perpendicular to the periodicity of the stripes. The same type of superstructure is also observed in a wide range of temperatures below the stripe formation temperature. We present a combined experimental and theoretical study of this superstructure of Pd on W(110) and investigate its influence on the appearance of the linear mesoscopic stripes. By means of low-energy electron diffraction and low-energy electron microscopy we show that it has a far more peculiar dependence on temperature and coverage than expected from a regular surface reconstruction. Using density-functional theory, we model the Pd superstructures as periodic vacancy-line type configurations and investigate their energetics and elastic properties. From our calculated surface stresses and anisotropies for the vacancy-line configurations, and based on the continuum elasticity theory, we demonstrate quantitatively that the vacancy-line type of structure is a prerequisite for the formation of the linear mesoscopic stripes. Moreover, we show that the physics driving the formation of the internal superstructure is very similar to the one at play in forming the mesoscopic stripes themselves.