有机半导体中压力增强热输运的起源
Origins of Pressure-Enhanced Thermal Transport in Organic Semiconductors
- Montanuniversität Leoben（莱奥本矿业大学）
- Graz University of Technology（格拉茨工业大学）
- TU Wien（维也纳科技大学）
- Columbia University（哥伦比亚大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究结合机器学习势与维格纳输运方程，揭示压力通过增强分子间键刚性、提高声子群速度并抑制散射，从而显著提升有机半导体萘的热导率。
AI中文摘要：
虽然已知压力会显著改变有机半导体的电子性质，但其对热导率的影响仍知之甚少。我们将机器学习势与维格纳输运方程相结合，计算作为模型系统的晶态萘的压力依赖性热导率。当训练中包含高压参考数据时，我们的模拟定量再现了实验中观察到的压缩萘热导率的显著增加。最重要的是，我们的结果揭示了这种巨大增强的微观起源：压力尤其增强了分子间键的刚性，增加了载热声子的群速度，同时抑制了阻碍带内（传播）热输运的散射。相比之下，带间（隧穿）输运由于不同声子带之间光谱重叠的减少而相对减弱。这些发现为软分子材料中的热传导提供了基本见解，并表明增强分子间相互作用（此处通过施加压力）可用于调控分子晶体中的热输运。
英文摘要：
While pressure is known to dramatically alter the electronic properties of organic semiconductors, its impact on their thermal conductivity remains poorly understood. We combine machine learned potentials with the Wigner transport equation to compute the pressure-dependent thermal conductivity of crystalline naphthalene as a model system. When high-pressure reference data are included in the training, our simulations quantitatively reproduce the experimentally observed dramatic increase in thermal conductivity for compressed naphthalene. Most importantly, our results reveal the microscopic origin of this massive enhancement: pressure stiffens especially the intermolecular bonds, increasing the group velocities of heat-carrying phonons and simultaneously suppressing the scattering that impedes intraband (propagation) thermal transport. In contrast, interband (tunneling) transport is relatively weakened by a reduced spectral overlap between different phonon bands. These findings provide fundamental insights into heat conduction in soft molecular materials and suggest that strengthening intermolecular interactions, here, via applying pressure can be used to tune thermal transport in molecular crystals.
