破译保林的第三规则:揭示强烈的无和性和特别低的热导电性在TlAgSe热电的热电
Riddhimoy Pathak1, Sayan Paul2, Subarna Das1
1New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Jakkur P.O., Bangalore, 560064, India.
Angewandte Chemie (International ed. in English)
|July 26, 2024
概括
保林的第三定律解释了由于原子排斥而导致的TLAgSe的低导热性. 这种不稳定性抑制了晶格导热率 (κL),为材料设计提供了新的策略.
科学领域:
- 材料科学 材料科学 材料科学
- 固态物理 固态物理
- 晶体学 晶体学是指结晶学.
背景情况:
- 低晶格导热率 (κL) 对于热电和热屏障应用至关重要.
- 了解原子动力学和化学键是控制 κL.L.的关键.
- 保林的第三个经验规则为格子不稳定提供了一个减少 κL 的机制.
研究的目的:
- 调查 TlAgSe 中超低晶格导热率背后的机制.
- 为了证明由阴离子排斥驱动的晶格不稳定性的存在和影响.
- 为保林在三元化物中的第三个经验规则提供实验证据.
主要方法:
- 同步射线X射线对分布函数 (PDF) 分析探测局部结构.
- 第一个原则密度函数理论 (DFT) 计算.
- 对原子动力学和晶格导热性的分析.
主要成果:
- 在边缘共享的AgSe4四面体中确定了Ag-Ag排斥,导致格子不稳定.
- 在 TlAgSe.中,在 573 K 时观察到 0.17 W/m·K 的超低晶格导热率 (κL).
- Ag和Tl原子的相关声导致无声性,低能光学声子和压抑的声音速度.
结论:
- 直接的实验证据证实了保林的第三个经验规则控制了TLAgSe中的格子不稳定性.
- 该研究强调了动态格子扭曲作为减少晶体固体中 κL 的策略.
- 接近费米水平的充满的抗结合状态有助于软和不和的晶格.
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