对最小格子导热率的统一理解
Yi Xia1, Dale Gaines2, Jiangang He3
1Department of Mechanical and Materials Engineering, Portland State University, Portland, OR 97201.
概括
我们开发了一个最小格子导热率模型,揭示了晶体的普遍下界. 这一发现与现有的模型形成鲜明对比,并有助于设计具有低导热性的材料.
科学领域:
- 凝聚物质物理学 凝聚物质物理学
- 材料科学 材料科学 材料科学
- 计算材料科学科学 计算材料科学
背景情况:
- 了解格子导热率 (κL) 对于热管理和热电应用至关重要.
- 现有的模型,如声子气体模型,在预测复杂和无序材料的 κL 方面存在局限性.
- 需要一个统一的理论框架,用于晶体和玻璃材料的热传输.
研究的目的:
- 提出和验证最低格子导热率 (κL) 的第一原则模型.
- 为了研究 κL 在无机化合物中的普遍行为.
- 为热传输机制提供见解,并指导材料设计特定的热性能.
主要方法:
- 开发了一个统一的理论模型,用于晶体和玻璃的热传输.
- 将模型应用于成千上万的无机化合物,以分析 κL 的行为.
- 利用图形网络和随机森林机器学习模型在无机晶体结构数据库 (ICSD) 中进行预测.
主要成果:
- 确定了在高温下在晶体中 (∼0.12.6 W/~m K) 对同位素平均 κL 的通用,结构独立的下限.
- 证明 κL 是从下面的边界,不管有什么混乱,但运输通道的重要性 (声气与扩散) 是依赖于混乱的.
- 根据实验测量超低 κL.对热电材料的验证预测.
结论:
- 拟议的模型提供了对最小格子导热率的统一理解.
- 对声子气体和扩散贡献的洞察力为理性材料工程提供了基础.
- 该研究弥合了与卡希尔-沃森-波尔 (CWP) 等现有模型的知识差距,解释了它们的范围和局限性.
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