由于结构动态不稳定性而引起的矿双酸盐中的异常玻璃状导热性
Alexandre Henriques1, Mariana S L Lima1, Gøran J Nilsen2
1Institute of Physics, University of São Paulo, São Paulo, 05508-090, Brazil.
概括
对BaBiO3的研究显示,由于其类似玻璃的行为,其导热率极低. 一种涉及BiO6八面体旋转的新型声子散射机制可能导致这种抑制.
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
背景情况:
- 了解导热性对于设计新的功能性材料至关重要.
- 在原始晶体中超低的导热率是一个重大挑战.
研究的目的:
- 为了研究单晶BaBiO3在扩大温度范围 (1.5-400K) 的导热率 (κ(T)).
- 阐明负责BaBiO3.3中观察到的异常热传输特性的机制.
主要方法:
- 实验测量热导率 κ(T) 从1.5K到400K.
- 理论计算包括三声波和同位素乱散射.
- 对声子散射机制的分析,包括道两层系统的潜在贡献.
主要成果:
- 观察到异常的类似玻璃的导热性,在低温下依赖T^2和平原从20K到260K.
- 测量室温 κ ≈ 1.6 W m^-1 K^-1,与计算一致.
- 实验中的 κ(T) 偏离了300 K以下的计算,表明存在额外的散射机制.
结论:
- 与BiO6八面体旋转相关的道两层系统被提议作为额外的声子散射机制.
- 这种机制解释了BaBiO3在较低温度下抑制的导热性.
- 这些发现对化BaBiO3和异构结构设计中的超导机制有影响.
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