把分析型嵌入原子法(AEAM)和晶格动力学理论相结合,在三维布喇菲晶格振动模型的基础上模拟了面心立方金属Au、Ag、Pt、Cu和Ni沿[00ζ]、[0ζζ]、[ζζζ]和[0ζ1]4个对称方向的声子色散曲线.结果表明:模拟曲线与实验点线符合的较好,特别在低频附近二者几乎一致,而在纵波模(L)q=(001)2π/a,q=(111)2π/a和横波模(T2)q=(011)2π/a三个布里渊区边界点附近,两者在数值上略有差异;沿[00ζ]和[ζζζ]两个高对称性方向上,横模T1和T2简并为一个横模T;在同一对称方向上,五种面心立方金属Au、Ag、Pt、Cu和Ni的频率随原子质量的增大而依次减小.
Phonons dispersion curves for Fcc metals Au,Ag,Pt,Cu and Ni along symmetry directions ,, and respectively,have been simulated by combining the analytic embedded atom method(AEAM) with the theory of lattice dynamics based on three-dimensional lattice vibration model.The results show that the simulated phonons dispersion curves are a good fit for small wave vector q,and have a very similar shape for the longitudinal mode(L) near q=(001)2π/a,q=(111) 2π/a,and the transverse mode(T2) q=(011)2π/a although the actual degree of fit varies somewhat.Along both and directions,two transverse modes T1 and T2 merges into a transverse mode T due to four and six fold rotation symmetry about these two directions.The vibration frequency along same symmetry direction increases for Au,Ag,Pt,Cu and Ni successively with the mass of Au,Ag,Pt,Cu and Ni decreasing successively.
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