在X射线衍射和总散射揭示的萨马六化物中负热膨胀的电子起源
Li Li1, Martin T Dove2,3,4, Zhongsheng Wei4
1College of Science, Civil Aviation Flight University of China, 46 Nanchang Road, Guanghan, 618307, Sichuan, China.
Physical chemistry chemical physics : PCCP
|February 19, 2024
概括
萨马六化物表现出负热膨胀 (NTE). 实验分析表明,这是由于电子效应,即原子随着温度的增加而失去电子,而不是声子机制.
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
- 固态化学 固态化学
背景情况:
- 萨马六化物 (SmB) 是一种具有负热膨胀 (NTE) 的材料.
- 像普鲁士蓝调这样的类似材料中的NTE通常归因于语音机制.
- 之前的DFT计算表明,在SmB6中,声子机制不太可能存在.
研究的目的:
- 为了实验性地研究萨马里六化物中负热膨胀背后的机制.
- 为了确定SmB6的依赖温度的结构行为.
主要方法:
- 实验性X射线衍射分析.
- 配对分布函数分析.
- 在20-300K的温度范围内进行测量.
主要成果:
- 两种X射线衍射和对分布函数分析都揭示了温度依赖的原子间距离.
- 观察到的结构变化与语音驱动的NTE机制不一致.
- 结果支持负热膨胀的电子起源.
结论:
- 萨马六化物中负热膨胀是由于电子效应引起的.
- 随着温度的增加,萨马原子失去电子,导致离子半径更小.
- 这种电子机制解释了在SmB6中观察到的NTE行为.
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