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应用改进分析型嵌入原子法模型和晶格动力学理论,计算了金属钽和钨以及B2型钽钨有序合金的原子力常数和动力学矩阵,模拟了金属钽和钨沿[ζ00]、[ζζ0]和[ζζζ]三个对称方向以及B2型钽钨有序合金沿[ζζ0]、[11ζ]、[ζζζ]和[ζ00]四个对称方向的声子色散曲线,并分析了B2型钽钨有序合金的振动特性.结果表明:金属钽和钨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;B2型钽钨有序合金中既有声频振动支又有光频振动支,光频支的振动频率均大于声频支的振动频率,且光频带和声频带之间由宽度约为0.82THz的空带隔开;在[ζζ0]对称方向上有六个独立振动模,在[11ζ]、[ζζζ]和[ζ00]对称方向上六个振动模均兼并为四个独立振动模,且各振动支的振动方向不尽相同.
The atomic force constants and kinetic matrices of tantalum and tungsten tantalum and B2 type tantalum tungsten ordered alloys were calculated by using the improved analytic embedded atomic model and the lattice dynamics theory. The dependences of the tantalum and tungsten on [ζ00], [ζζ0 ] And [ζζζ] and the phonon dispersion curves along the four symmetric directions [ζζ0], [11ζ], [ζζζ] and [ζ00] of the B2-type tantalum tungsten ordered alloy, Order a copy of this thesis The results show that the simulation results of the phonon dispersion curve of metal tantalum and tungsten are in good agreement with the experimental data, especially near the low frequency. In the B2 type tantalum tungsten ordered alloys, The optical frequency vibration branch is supported by an optical frequency vibration branch. The vibration frequency of the optical branch is greater than the vibration frequency of the audio branch. The optical frequency band and the sound frequency band are separated by a vacant band of about 0.82 THz width. In the [ζζ0] symmetrical direction Six independent modes of vibration, the six modes in the [11ζ], [ζζζ] and [ζ00] symmetric directions all merge into four independent modes, and the vibration directions of the different vibrating branches are different.