Shi Lin, Ni Jun
Department of Physics and Key Laboratory of Atomic and Molecular Nanoscience (Ministry of Education), Tsinghua University, Beijing 100084, People's Republic of China.
Phys Rev Lett. 2006 Sep 22;97(12):126105. doi: 10.1103/PhysRevLett.97.126105. Epub 2006 Sep 21.
The epitaxial growth has a distinct kinetic feature that the lateral surface diffusion is faster than the longitudinal bulk diffusion. We show there is an ordering-orientation transition of alloy films with the change of growth rate due to this kinetic anisotropy. As an example, we have calculated the epitaxial growth of CoPt alloy films on the Pt buffer layer. We show the ordered structure of CoPt films changes from the L1(0) [001] (a compositional modulation along the [001] direction) variant to the L1(0) [100] variant with the increase of growth rate. This ordering-orientation transition also occurs with the decrease of temperature at adequate growth rate. Based on this mechanism, we propose a simple method to synthesize the ordering-orientation superlattices.
外延生长具有一个明显的动力学特征，即横向表面扩散比纵向体扩散更快。我们表明，由于这种动力学各向异性，合金薄膜会随着生长速率的变化发生有序 - 取向转变。例如，我们计算了在铂缓冲层上的钴铂合金薄膜的外延生长。我们发现，随着生长速率的增加，钴铂薄膜的有序结构从L1(0) [001]（沿[001]方向的成分调制）变体转变为L1(0) [100]变体。在适当的生长速率下，随着温度降低也会发生这种有序 - 取向转变。基于这一机制，我们提出了一种合成有序 - 取向超晶格的简单方法。
