发表机构
Bauman Moscow State Technical University; College of Physical Science and Technology, Bohai University; Department of Engineering Mechanics, Tsinghua University（鲍曼莫斯科国立技术大学; 渤海大学物理科学与技术学院; 清华大学工程力学系）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
提出PhonoMC，一种基于占据数的偏差蒙特卡洛方法，用于含温度依赖散射的声子输运模拟，通过固定偏差参考和局部温度依赖散射，高效且准确地计算纳米尺度热输运。
AI 中文摘要
纳米尺度的自热现象涉及声子在受限几何结构、材料界面以及温度场中的输运，在这些过程中散射率可能发生显著变化。我们开发了PhonoMC，一种基于占据数的偏差蒙特卡洛方法，用于在弛豫时间近似下求解声子玻尔兹曼输运方程。该方法保留一个固定的平衡态作为偏差参考，同时利用由所表示的能量重建的局部温度来评估模式依赖的散射率。碰撞通过单独确定的弛豫温度进行更新，以保证每个时间步内的能量守恒，并且通过改变载流子占据数而非持续添加计算粒子来引入规定的晶格加热。对于穿过100纳米硅薄膜的跨平面输运，偏差公式在ΔT=100 K且载流子数为10^5时，重现了全占据数热通量，同时将其标准差降低了约3.3倍。相比之下，将散射率固定在300 K时，在ΔT=250 K下热通量被高估了23.7%。对硅薄膜的计算区分了有限长度效应与表面散射抑制效应，并使用Si/3C-SiC双层结构来研究界面热阻。该方法进一步应用于类似FinFET结构的局部加热，其中将较低层的硅衬底替换为更高热导率的3C-SiC，由于受限硅区域和Si/SiC界面带来的额外热阻，导致热点温度更高。这些结果表明，在模式分辨的纳米尺度热输运蒙特卡洛描述中，可以将固定的偏差参考与局部温度依赖的散射及持续的热沉积相结合。
英文摘要
Nanoscale self-heating involves phonon transport across confined geometries, material interfaces, and temperature fields over which the scattering rates can vary substantially. We develop PhonoMC, an occupation-based deviational Monte Carlo method for solving the phonon Boltzmann transport equation within the relaxation-time approximation. A fixed equilibrium state is retained as the deviational reference, while the local temperature reconstructed from the represented energy is used to evaluate mode-dependent scattering rates. Collisions are updated with a separately determined relaxation temperature to conserve energy over each time step, and prescribed lattice heating is introduced by changing carrier occupations rather than continuously adding computational particles. For cross-plane transport through a 100-nm Si film, the deviational formulation reproduces the full-population heat flux while reducing its standard deviation by a factor of approximately 3.3 at \(ΔT=100\)~K with \(10^5\) carriers. In contrast, keeping the scattering rates fixed at 300~K overestimates the heat flux by 23.7\% at \(ΔT=250\)~K. Calculations of Si thin films distinguish finite-length effects from surface-scattering suppression, and Si/3C-SiC bilayers are used to examine interfacial thermal resistance. The method is further applied to localized heating in FinFET-like structures, where replacing the lower Si substrate with higher-conductivity 3C-SiC leads to a higher hotspot temperature because of the additional resistance associated with the confined Si region and the Si/SiC interface. These results show that a fixed deviational reference can be combined with local temperature-dependent scattering and sustained heat deposition in a mode-resolved Monte Carlo description of nanoscale thermal transport.
