不稳定性控制无形固体的低频振动谱
Surajit Chakraborty1, Roshan Maharana1, Smarajit Karmakar1
1Tata Institute of Fundamental Research, Hyderabad 500046, India.
The Journal of chemical physics
|July 14, 2025
概括
无形固体表现出不寻常的低频振动. 这项研究揭示了边界不稳定性决定了它们的振动状态密度 (VDoS) 的指数,对于不同的弹性分支观察到不同的缩放规律.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学是一种材料科学.
背景情况:
- 无形固体具有异常的机械和热性能,原因是超出了德拜预测的过多的低频振动模式.
- 在无形固体的低频振动密度状态 (VDoS) 中观察到功率定律行为,但指数仍在争论中.
研究的目的:
- 调查边界条件诱导的不稳定性在无形固体中VDoS指数变化的作用.
- 识别不同的弹性分支及其对VDoS扩展的影响.
主要方法:
- 在不同的边界条件和变形下模拟无形固体.
- 弹性分支的分类为"虚构" (易发生塑性不稳定) 和"真实" (可通过弹性变形获得).
- 对不同分支类型和系统大小的VDoS缩放规律的分析,包括带有和没有剩余应力的分析.
主要成果:
- 虚构分支显示VDoS扩展为D(ω) ∼ ω3,而真实分支显示D(ω) ∼ ω5.5.5.
- 没有区分分支的集成平均值产生了一个常见的指数,接近4.
- 放松固体到剪切最小值 (消除残余应力) 会导致D (ω) ~ ω6.5缩放.
- 虚构分支的普及率随着系统的大小而增加.
结论:
- 边界诱导的不稳定性显著影响无形固体中低频VDoS扩展.
- 提出了两个限制行为:D(ω) ∼ ω3随着系统大小的增加 (没有解决不稳定性) 和D(ω) ∼ ω6.5在去除剩余应力时.
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