摘要
基于改进分析型嵌入原子法模型和晶格动力学理论,在谐和近似下重现了面心立方金属锶沿[00ζ]、[0ζζ]、[ζζζ]和[0ζ1]四个高对称方向上声子谱的实验结果,预测了沿[0.5 1-αα]、[0.5+α1-α0]、[0.5+α0.5+α0.5-2α]和[α1-αα]四个低对称方向上的声子谱,并讨论了不同对称方向上不同色散支的兼并特征和振动性质。结果发现:高对称方向上声子谱的计算结果与实验结果非常吻合,在低频附近二者完全一致。在[00ζ]和[ζζζ]两个高对称方向上,振动方向不同的两个声频横波模AT1和AT2兼并为一个声频横波模AT;在其它高对称方向上没有兼并现象,各个色散支的振动方向和振动模式不随波矢变化。
Within the harmonic approximation, the experimental results of the phonon spectra in fcc metal strontium along four high-symmetry directions [00ζ], [0ζζ], [ζζζ] ,and [0ζ1] were reproduced,and the phonon spectra of strontium along four low-symmetry directions [0.5 1-α α],[0.5＋α 1-α 0],[0.5＋α 0.5＋α 0.5-2α] and [α 1-α α] were predicted based on the modified analytic embedded atom method and the theory of lattice dynamics. Then the merger characteristics and vibration properties of different dispersion branches at different directions were discussed. The results show that the calculated results are in agreement with available experimental results along high-symmetry directions, especially for lower frequency rather than at the first Brillouin zone boundaries. Along [00ζ] and [ζζζ] directions, two acoustic dispersion branches with different vibrations AT1 and AT2 merge into a dispersion branch AT. There are no merger phenomena observed along other directions, and the vibration directions and vibration modes of the dispersion branches does not change with wave vector.
出处
《材料导报》
EI
CAS
CSCD
北大核心
2015年第4期136-140,共5页
Materials Reports
基金
陕西省教育厅科研计划项目(14JK1301)
陕西省自然科学基金(2012JM1011)
关键词
声子谱
振动性质
改进分析型嵌入原子法
高对称方向
低对称方向
phonon spectrum, vibration property, modified analytic embedded atom method, high-symmetry direction, low-symmetry direction
