热胀冷缩是自然界中一种普遍现象。然而，具有热缩冷胀反常物理性质并具有应用价值的材料较为罕见，人们对负热膨胀的认识也非常有限。本项目提出一类自主设计的新型负热膨胀化合物，并赋予其丰富的光学和电学性质，使其在非常大的温度范围（约150~1500K）具有优异的负热膨胀性质的同时，具有特殊的光、电功能。能同时集多种功能于一身的负热膨胀化合物极其罕见，在未来光学和光电器件、电子器件及精密仪器等领域极具应用潜力。本项目将通过多种手段制备该类负热膨胀功能化合物，并通过不同温度等外场作用下的结构分析和光、电等综合性能测试揭示其结构、负热膨胀性质、光学性质和电学性质，通过实验结合第一性原理计算阐明其结构与物性关系及物理机制。本项目研究不仅将拓展人们对负热膨胀物理机制的认识，同时也将为负热膨胀家族增添性能优异的新成员，为此类新型材料的器件化应用奠定理论和实验基础。

Thermal expansion is a popular phenomenon in nature. Nevertheless, materials exhibiting thermal contraction and being useful are few and hence the understanding on the phenomenon of negative thermal expansion (NTE) is very limited. In this proposal, we bring forward a novel type of NTE materials and endow them special optical and electrical properties, making them not only exhibit NTE in a wide temperature scope (150-1500K), but also possess optical and electrical functional. Integrating multifunctional in one NTE material has rarely been seen and has potential applications in optical, electrical and optoelectronic devices and precision instruments. We plan to synthesize such new compounds through different methods, investigate their structure, thermal contraction, optical and electrical properties by synthetic structural, optical and electrical measurements and analyses. The structure-property correlations and the physics behind are to be revealed by experiments and first-principles calculation methods. The implementation of this proposal will put forward our understanding on the NTE mechanisms, add a group of new members with multifunction for the NET family and lay a solid foundation for device application of these materials.