Phonon Dispersion of Molybdenum under High-Pressure:A Study by Modified Analytic Embedded Atom Method
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摘要: 应用改进分析型嵌入原子法模型计算了不同高压下金属钼的原子力常数和动力学矩阵,重现了压强下金属钼沿[00ζ]、[0ζζ]和[ζζζ]3个高对称方向上声子色散的实验结果,预测了钼在压强分别为60、80和100 GPa时的声子色散曲线。结果表明:压强分别为0.1 MPa、17 GPa和37 GPa时金属钼的声子色散曲线的模拟结果和实验值符合较好,特别在低频附近二者几乎一致,而在布里渊区的边界点附近,两者在数值上略有差异;在压强分别为60、80和100 GPa时所预测的声子色散曲线和常压下声子色散曲线的形状都非常相似;高压下所有振动支的振动频率均高于常压下的振动频率,且振动频率随压强的增大而增大。
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关键词:
- 声子色散关系 /
- 高压 /
- 数值模拟 /
- 改进分析型嵌入原子法
Abstract: Based on the modified analytic embedded atom method, we calculated the atomic force constants and the dynamical matrices of the metal molybdenum under different high pressures, and then reproduced the experimental results of the phonon dispersion in bcc molybdenum along three highly symmetrical directions [00ζ], [0ζζ] and [ζζζ] under pressures.In addition, we predicted the phonon dispersion curves of molybdenum under high pressures of 60, 80 and 100 GPa.The results show that our simulated results at high pressures of 0.1 MPa, 17 GPa and 37 GPa agree fairly well with the available experimental results, especially for lower frequencies rather than within the first Brillouin zone boundaries.The shapes of the dispersion curves predicted under high pressures of 60, 80 and 100 GPa are very similar to that under normal pressures.The vibration frequencies of molybdenum in all vibration branches under high pressures are all larger than the results achieved under normal pressures, and they increase along with the high pressures of 60, 80 and 100 GPa. -
表 1 金属钼的模型参数
Table 1. The model parameters of metal Mo
n F0/(eV) α/(eV) k-1/(eV) k0/(eV) k1/(eV) k2/(eV) k3/(eV) k4/(eV) 0.52 3.72 0.0475 1071.46 -4872.40 8859.23 -8045.30 3644.56 -658.07 -
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