中子散射技术在热电材料研究中的应用

发布时间：2018-07-04 23:22

本文选题：热电性能 + 热导率　；参考：《西北大学学报(自然科学版)》2017年06期

【摘要】：热电材料是一种可以直接将热能转换为电能的有效能源材料,具有较高稳定性及简单结构等特点,但是低的能效限制了它的应用。因此,如何有效提高热电材料的效率是当下一个研究热点。"声子玻璃-电子晶体"(即高电导率低热导率材料)概念为设计理想的热电材料提供了一个明确的思路:目前,剪裁能带结构和降低晶格热导是改善热电性能的两个主流方向。其中降低晶格热导的方法主要集中在微观上改变声子色散关系,包括掺杂点缺陷和重原子、构造复杂的晶体结构和衍生非简谐性原子键、引入ratteling原子等等。中子散射技术(包括中子衍射、非弹性中子散射、中子漫散射等技术)可以从晶体结构、原子占位、均方位移、结构内应力、声子色散关系与态密度等多方面研究与晶格热导率相关的微观机制,在热电材料的研究中起着重要的作用。
[Abstract]:Thermoelectric material is an effective energy material which can convert heat energy directly into electric energy. It has the characteristics of high stability and simple structure, but its application is limited by low energy efficiency. Therefore, how to effectively improve the efficiency of thermoelectric materials is the current research hotspot. " The concept of "phonon glass-electron crystal" (that is, high conductivity and low thermal conductivity material) provides a clear idea for the design of ideal thermoelectric materials. At present, cutting band structure and reducing lattice thermal conductivity are two main directions to improve thermoelectric properties. The methods to reduce the lattice thermal conductivity are mainly focused on changing the phonon dispersion relationship, including doping point defects and heavy atoms, constructing complex crystal structures and derivation of anharmonic atomic bonds, introducing ratteling atoms, and so on. Neutron scattering techniques (including neutron diffraction, inelastic neutron scattering, neutron diffuse scattering, etc.) can be used from crystal structure, atomic occupation, mean square displacement, internal stress, etc. The relationship between phonon dispersion and density of state, which plays an important role in the study of thermoelectric materials, is studied in many aspects, such as the microscopic mechanism related to the lattice thermal conductivity.
【作者单位】：上海交通大学物理与天文学院;
【基金】：科技部国家重点研发基金资助项目(2016YFA0300500)
【分类号】：O571.5;TB34

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