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arXiv 2209.11201cond-mat.mtrl-sci
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平台以上玻璃的热导率:第一性原理理论及其应用

Thermal conductivity of glasses above the plateau: first-principles theory and applications

Michele Simoncelli, Francesco Mauri, Nicola Marzari

摘要:

从第一性原理预测玻璃的热导率迄今为止一直是一个过于复杂的问题。事实上,过去的工作已经强调了在使用已建立的Allen-Feldman或Green-Kubo公式实现关于长度和/或时间尺度的计算收敛方面的挑战,赞同包含数千个原子的原子模型的概念-因此超出了第一性原理计算的能力-需要描述玻璃的热导率。此外,这些已建立的公式要么忽略了非谐性(艾伦-费尔德曼),要么错过了原子振动的玻色-爱因斯坦统计(格林久保),从而留下了关于这些效应的相关性的问题。在这里,我们提出了一个第一性原理配方,以解决上述平台,它可以全面考虑结构无序,非谐性和量子玻色-爱因斯坦统计的影响的玻璃的热导率。该协议结合了Wigner制定的热传输与收敛加速技术,并验证了在玻璃态二氧化硅使用第一性原理计算和量子精确的机器学习的原子间的潜力。我们表明,含有少于200个原子的玻璃体二氧化硅模型已经可以重现在宏观极限的热导率和非谐性可以忽略不计的影响玻璃体二氧化硅中的热传输。我们讨论了决定高温下电导率趋势的微观量,强调了在高于平台的温度范围内(50<T <450 K)计算与实验的一致性,在该温度范围内辐射效应仍然可以忽略不计。

英文摘要:

Predicting the thermal conductivity of glasses from first principles has hitherto been a prohibitively complex problem. In fact, past works have highlighted challenges in achieving computational convergence with respect to length and/or time scales using either the established Allen-Feldman or Green-Kubo formulations, endorsing the concept that atomistic models containing thousands of atoms -- thus beyond the capabilities of first-principles calculations -- are needed to describe the thermal conductivity of glasses. In addition, these established formulations either neglect anharmonicity (Allen-Feldman) or miss the Bose-Einstein statistics of atomic vibrations (Green Kubo), thus leaving open the question on the relevance of these effects. Here, we present a first-principles formulation to address the thermal conductivity of glasses above the plateau, which can account comprehensively for the effects of structural disorder, anharmonicity, and quantum Bose-Einstein statistics. The protocol combines the Wigner formulation of thermal transport with convergence-acceleration techniques, and is validated in vitreous silica using both first-principles calculations and a quantum-accurate machine-learned interatomic potential. We show that models of vitreous silica containing less than 200 atoms can already reproduce the thermal conductivity in the macroscopic limit and that anharmonicity negligibly affects heat transport in vitreous silica. We discuss the microscopic quantities that determine the trend of the conductivity at high temperature, highlighting the agreement of the calculations with experiments in the temperature range above the plateau where radiative effects remain negligible (50<T <450 K).

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