Influence of surface stress on the equilibrium shape of strained quantum dots
Influence of surface stress on the equilibrium shape of strained quantum dots
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DOI：
10.1103/physrevb.58.4566
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发表时间：
1998-08-15
影响因子：
3.7
通讯作者：
Pehlke, E
中科院分区：
文献类型：
--
作者：
Moll, N;Scheffler, M;Pehlke, E
InAs量子点的平衡形状（即，用密度泛函理论（DFT）计算了GaAs（001）衬底上生长的无位错、应变岛（尺寸大于或等于10000个原子）的微观参数、表面能和表面应力，并结合弹性理论计算了长程应变场和应变弛豫。特别是，我们报告的DFT计算的表面应力和分析的应变对量子点的各个方面的表面能的影响。在以往的研究中，表面应力被忽略。此外，边缘能量的岛形状的影响进行了简要的讨论。从这些岛屿的平衡形状的知识，我们解决的问题是否实验观察到的量子点对应于热平衡结构，或者如果它们是生长动力学的结果。
The equilibrium shapes of InAs quantum dots (i.e., dislocation-free, strained islands with sizes greater than or equal to 10 000 atoms) grown on a GaAs (001) substrate are studied using a hybrid approach that combines density functional theory (DFT) calculations of microscopic parameters, surface energies, and surface stresses with elasticity theory for the long-range strain fields and strain relaxations. In particular we report DFT calculations of the surface stresses and analyze the influence of the strain on the surface energies of the various facets of the quantum dot. The surface stresses have been neglected in previous studies. Furthermore, the influence of edge energies on the island shapes is briefly discussed. From the knowledge of the equilibrium shape of these islands, we address the question whether experimentally observed quantum dots correspond to thermal equilibrium structures or if they are a result of growth kinetics.