FCC金属结构稳定性和声子谱的MAEAM研究

应用改进分析型嵌入原子方法(MAEAM)计算fcc金属的结构稳定性和声子谱.考虑更远邻原子之间的相互作用,提出新的两体势函数,并采用新的截尾处理函数和加强光滑连接条件.通过拟合单空位迁移能、结合能、三个独立弹性常数及晶体平衡条件,确定了模型参数.在体积不变条件下,计算金属不同结构的能量,说明Ag、Al、Au、Cu、Ir、Ni、Pd、Pt和Rh的fcc结构比较稳定.它们的能量-体积曲线与Rose方程结果基本-致,进-步说明了体积变化时的结构稳定性.同时发现100]、110]和111]三个方向声子谱的计算结果符合实验值和其它计算结果.

MAEAM Study on Structure Stability and Phonon Spectrum of FCC Metals

With a modified analytical embedded atom method(MAEAM),structure stability and phonon spectra of fcc metals are calculated.A pair-potential function was proposed considering farther neighbor atomic interaction.A new truncated function and an enhanced smooth connection condition are used for the cutoff of pair potential.Model parameters are determined through fitting mono-vacancy migration energy,cohesion energy,three independent elastic constants and an equilibrium condition.Under same volume,we calculated binding energies of various metal structures.It shows that fcc structures of Ag,Al,Au,Cu,Ir,Ni,Pd,Pt and Rh are more stable.Energy-volume curves of these metals fit the results of Rose equation.Structure stabilities are proved with volume change.Phonon dispersions of fcc metals along, and directions agree with experiments and other calculations.