Ballistic phonon lensing by the non-planar interfaces of embedded nanoparticles
Ballistic phonon lensing by the non-planar interfaces of embedded nanoparticles
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DOI：
10.1088/1367-2630/ad025a
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发表时间：
2023-10
影响因子：
3.3
通讯作者：
Theodore Maranets;Yan Wang
中科院分区：
文献类型：
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作者：
Theodore Maranets;Yan Wang
在这项工作中，我们通过分子动力学模拟研究了入射到嵌入纯晶体内的掺杂球形纳米颗粒上的弹道声子波的散射行为。这项工作的独特之处在于，我们还对掺杂薄板上的弹道声子散射进行了共轭模拟，以比较和对比非平面异质界面（纳米粒子）和平面异质界面（薄板）的散射。对实空间和倒易空间中波动力学的分析表明，纳米颗粒散射系统中的声子模式转换是由于未报告的“声子透镜”效应所致，其中声子波传播通过纳米颗粒非平面界面的折射和反射而改变。研究表明，模式转换的具体状态会随着透镜特性的变化而变化，透镜特性随纳米颗粒尺寸的变化而变化。最重要的是，薄板的声子散射中不存在透镜现象，因此导致平面和非平面界面之间的散射行为存在差异。
In this work, we investigate the scattering behavior of a ballistic phonon wave incident on a dopant spherical nanoparticle embedded within a pure crystal through molecular dynamics simulations. Unique to this work, we also conduct conjugate simulations of ballistic phonon scattering on a dopant thin slab to compare and contrast scattering by non-planar heterogeneous interfaces (nanoparticle) and planar heterogeneous interfaces (thin slab). Analysis of the wave dynamics in real and reciprocal spaces reveal phonon mode-conversion in the nanoparticle scattering system is due to an unreported ‘phonon lensing’ effect where the phonon wave propagation is altered by refraction and reflection through the non-planar interfaces of the nanoparticle. The specific states of mode-conversion is shown to change with the character of the lensing that varies with nanoparticle size. Most significantly, the lensing phenomenon is absent in the phonon scattering by the thin slab and consequentially, results in differences in the scattering behaviors between the planar and non-planar interfaces.