Wave propagation in lattice based on Tersoff potential
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摘要: 波动传播特性是研究材料动力学行为的基础,宏观尺度连续介质波动理论研究已十分完善。随着微纳尺度材料和结构的深入应用,晶格尺度介质波动特性的研究越来越得到关注。本文在晶格间的Tersoff势作用下分别研究单一晶格体系和多晶体系中的波动传播特性。首先,在微振动条件下,基于晶格间线性作用、Tersoff势作用和含缺陷的Tersoff势作用三种情况,研究了单一晶格体系中格波的传播,得到了格波波速和角频率关系。其次,分别以碳晶格和硅晶格为例,应用有限差分方法,研究了三种势作用下单一晶格体系中的波动传播过程,讨论了入射速度对位移峰值和受力峰值的影响,揭示出单一晶格体系中波动传播与连续介质中波动传播的差异。最后,分别以金刚石和碳化硅为例,采用分子动力学模拟,研究了多晶体系中的波动传播特性。结果表明:多晶体系中波动传播特性与单一晶格体系存在差异,缺陷的存在对波动传播规律影响显著。本研究对于微纳尺度材料动力学性能的研究具有较好的参考意义。
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关键词:
Abstract: The propagation characteristics of waves are the basis for studying the dynamic behavior of materials, and the study of continuous medium wave theory at the macro scale is quite comprehensive. With the in-depth application of materials and structures at the micro and nano scales, research on the wave characteristics at the lattice scale is receiving increasing attention. In this article, the Tersoff potential interaction between lattices is applied to study the wave propagation characteristics in single lattice systems and polycrystalline systems, respectively. Firstly, in the case of micro vibrations, the propagation of lattice waves in a single lattice system was studied based on three conditions: linear interaction, Tersoff potential, and Tersoff potential with defects between lattices. The relationship between lattice wave velocity and angular frequency was obtained. Secondly, taking carbon and silicon lattices as examples, the finite difference method was applied to study the wave propagation process in a single lattice system under three different potentials, and the influence of incident velocity on displacement peak and force peak was discussed, revealing the difference in wave propagation between a single lattice system and a continuous medium. Finally, taking diamond and silicon carbide as examples, molecular dynamics simulations were used to study the wave propagation characteristics in polycrystalline systems. The results indicate that the wave propagation characteristics in polycrystalline systems are different from those in single lattice systems, and the presence of defects has a significant impact on the wave propagation. This study has good reference significance for the study of material dynamics performance at micro and nano scales.-
Key words:
- lattice dynamics /
- micro vibration /
- Tersoff potential /
- defect /
- molecular dynamics
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