在无序晶体中具有类似玻璃的导热性和声子传输机制
Guoliang Ren1, Junwei Che2, Hanchao Zhang3
1Shanghai Key Laboratory of High Temperature Materials and Precision Forming, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China. xiaofengzhao@sjtu.edu.cn.
Materials horizons
|January 24, 2024
概括
研究人员在有缺陷的晶体中发现了热传输的新机制,显示扩散式的声子,而不是低频的声子,主导热导率. 这一发现为设计先进的绝热材料提供了新的策略.
科学领域:
- 材料科学 材料科学 材料科学
- 凝聚物质物理学 凝聚物质物理学
- 固态化学 固态化学
背景情况:
- 超低导热率 (κ) 材料对于热电和热屏障涂层至关重要.
- 许多低-κ材料表现出异常的玻璃般的导热率 (κ) 与温度 (T) 相比.
- 在玻璃状 κ-T 关系背后的显微声子机制缺乏全面的理论模型.
研究的目的:
- 为了研究微观的声子机制,负责玻璃般的导热性在有缺陷的晶体.
- 用实验和计算方法重新研究稀土酸盐 (RE3TaO7) 中的声子热传输.
- 开发一种新的理论框架,用于理解和设计低Kn材料.
主要方法:
- 实验研究与原子学模拟相结合,达到1800 K.
- 在有缺陷的稀土酸盐 (RE3TaO7) 中对声子热传输的分析.
- 研究原子间键和对导热性的作用.
主要成果:
- 与不均的原子间结合相关的扩散类声子对总导热率贡献了70%以上.
- 这一发现挑战了传统的理解,即低频声子是主要的热载体.
- 由于桥梁效应,高的酸盐的导热率并不一定低于中的对应物.
结论:
- 已经证明了在有缺陷的结构中多式波热传输的新物理机制.
- 原子间键的不均性是调节导热性的关键因素.
- 这项工作通过控制原子间结合,为开发低-κ材料提供了新的策略.
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