失配性质对二维失配铝膜结构及位错形成的影响

来源期刊：有色金属科学与工程2011年第5期

论文作者：张凤林 周耐根 周浪

文章页码：18 - 23

关键词：位错；二维失配；分子动力学模拟；铝；薄膜晶体

Key words：dislocation ; two-dimensional misfit ; molecular dynamics simulation ; aluminum ; thin film crystals

摘    要：采用三维分子动力学模拟方法，使用Ercolessi和Adams建立的嵌入原子法(EAM)多体势函数，模拟了二维失配铝膜晶体中失配位错的形成过程，研究了失配性质对二维失配铝膜结构及其形核机制的影响结果显示：同等条件下，负失配度的临界厚度小于正失配度情况；负失配度较易出现失配位错；负失配度下位错的形成始于表层一个倒三角锥形的间隙原子团；正失配度下位错的形成始于表层原子的畸变区；结构稳定后，负失配度体系在表层挤出局部原子层；正失配度体系会出现塌陷。

Abstract:

The influences of the misfit nature on the structure of two-dimensional aluminum film and its nucleation mechanism are studied by using the methods of three-dimensional molecular dynamics simulation and many-body potential function of embedded atom method (EAM) created by Ercolessi and Adams, and simulating the processes of misfit dislocations in two-dimensional mismatch aluminum film crystal. The result shows that under the same conditions, the critical thickness of negative mismatch is smaller than that of positive mismatch; the negative mismatch is prone to misfit dislocation; the negative misfit dislocation is formed from gap atomic group in a downward-pointing triangle on its surface; the positive misfit dislocation is made from distorted region on atomic surface; when the structure is stable, the negative mismatching system will extrude local atomic layer on its surface; the positive mismatching system will start to collapse.