Embedded-atom potential for Fe and its application to self-diffusion on Fe(100)
Embedded-atom potential for Fe and its application to self-diffusion on Fe(100)
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DOI：
10.1016/j.susc.2006.02.010
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发表时间：
2006-05-01
期刊：
影响因子：
1.9
通讯作者：
Papaconstantopoulos, D. A.
中科院分区：
文献类型：
--
作者：
Chamati, H.;Papanicolaou, N. I.;Papaconstantopoulos, D. A.
我们通过拟合实验和第一原理结果构建了 Fe 的嵌入原子势。该电势以令人满意的精度再现了金属的 BCC 相和高温 FCC 相的晶格特性、表面能和点缺陷能。该电势与分子动力学模拟一起用于计算 BCC-Fe 和 FCC-Fe 的热膨胀、声子色散曲线、均方位移和元件的表面弛豫。此外。我们研究了 BCC-Fe(100) 表面上单个吸附原子在几种温度下的自扩散。确定了三种主要扩散机制的迁移能量和指前因子，并与可用的实验数据进行了比较。我们发现对角交换扩散过程在能量上优于直接跳跃机制，并且其迁移能量接近实验值。此外，与对角交换扩散过程相关的扩散系数比跳跃和非对角交换机制的扩散系数高大约一个数量级。 (c) 2006 Elsevier B.V. 保留所有权利。
We have constructed an embedded-atom potential for Fe by fitting to both experimental and first-principles results. The potential reproduces with satisfactory accuracy the lattice properties, surface energies and point defect energies for both BCC and the high temperature FCC phases of the metal. The potential was used in tandem with molecular-dynamics simulations to calculate the thermal expansion of both BCC-Fe and FCC-Fe, the phonon dispersion curves, mean-square displacements and surface relaxations of the element. In addition. we have studied self-diffusion of single adatoms on the BCC-Fe(100) surface at several temperatures. The migration energies and pre-exponential factors for three main diffusion mechanisms were determined and compared with available experimental data. We have found that the diagonal exchange diffusion process is energetically favored over the direct hopping mechanism and that its migration energy is close to the experimental value. Furthermore, the diffusion coefficient associated with the diagonal exchange diffusion process is about an order of magnitude higher than those of the hopping and the non-diagonal exchange mechanisms. (c) 2006 Elsevier B.V. All rights reserved.