Molecular Dynamics Simulation of Phonon Scattering at Silicon/Germanium Interfaces
Molecular Dynamics Simulation of Phonon Scattering at Silicon/Germanium Interfaces
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DOI：
10.1115/1.4001912
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发表时间：
2010-10
影响因子：
--
通讯作者：
Lin Sun;J. Murthy
中科院分区：
文献类型：
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作者：
Lin Sun;J. Murthy
用分子动力学波包方法研究了Si/Ge界面声子输运的细节。三种类型的接口进行了研究：一个光滑的接口，一个接口与随机粗糙度，和一个接口与有规律的图案粗糙度。每种情况下的声子transmittance计算作为一个函数的声子频率，粗糙度特征长度，和原子结构。对于光滑界面，MD模拟预测的透射率与基于连续介质假设的声学失配模型吻合得很好。粗糙界面的模拟结果表明，随机粗糙度是非相干声子散射的根源，降低了声子的透射率。周期性的结构，如有规律地图案化的粗糙度，在本文中引起强烈的声子波干涉，并可能恢复声子传输层厚度的增加。
Detailed phonon transport at Si/Ge interfaces is studied using the molecular dynamics wave-packet method. Three types of interfaces are investigated: A smooth interface, an interface with random roughness, and an interface with a regularly patterned roughness. The phonon transmissivity for each case is calculated as a function of phonon frequency, roughness characteristic length, and atomic structure. For a smooth interface, the transmissivities predicted by the MD simulations agree well with the acoustic mismatch model based on the continuum assumption. The rough interface simulation results indicate that random roughness is the source of incoherent phonon scattering and decreases the phonon transmission. Periodic structures such as the regularly patterned roughness employed in this paper cause strong phonon wave interference and may restore phonon transmission as the layer thickness increases.