Department of Physical Chemistry, University of Science and Technology Beijing, Beijing 100083, China.
Chem Soc Rev. 2015 Jun 7;44(11):3522-67. doi: 10.1039/c4cs00461b.
Negative thermal expansion (NTE) is an intriguing physical property of solids, which is a consequence of a complex interplay among the lattice, phonons, and electrons. Interestingly, a large number of NTE materials have been found in various types of functional materials. In the last two decades good progress has been achieved to discover new phenomena and mechanisms of NTE. In the present review article, NTE is reviewed in functional materials of ferroelectrics, magnetics, multiferroics, superconductors, temperature-induced electron configuration change and so on. Zero thermal expansion (ZTE) of functional materials is emphasized due to the importance for practical applications. The NTE functional materials present a general physical picture to reveal a strong coupling role between physical properties and NTE. There is a general nature of NTE for both ferroelectrics and magnetics, in which NTE is determined by either ferroelectric order or magnetic one. In NTE functional materials, a multi-way to control thermal expansion can be established through the coupling roles of ferroelectricity-NTE, magnetism-NTE, change of electron configuration-NTE, open-framework-NTE, and so on. Chemical modification has been proved to be an effective method to control thermal expansion. Finally, challenges and questions are discussed for the development of NTE materials. There remains a challenge to discover a "perfect" NTE material for each specific application for chemists. The future studies on NTE functional materials will definitely promote the development of NTE materials.
负热膨胀（NTE）是固体的一种有趣物理特性，是晶格、声子和电子之间复杂相互作用的结果。有趣的是，在各种类型的功能材料中发现了大量的 NTE 材料。在过去的二十年中，在发现 NTE 的新现象和机制方面取得了很好的进展。在本文综述中，NTE 在铁电体、磁性体、多铁体、超导体、温度诱导电子构型变化等功能材料中进行了综述。由于实际应用的重要性，强调了功能材料的零热膨胀（ZTE）。NTE 功能材料呈现出一种普遍的物理图景，揭示了物理性质和 NTE 之间的强耦合作用。铁电体和磁体都具有 NTE 的普遍性质，其中 NTE 由铁电有序或磁有序决定。在 NTE 功能材料中，可以通过铁电-NTE、磁-NTE、电子构型变化-NTE、开放骨架-NTE 等耦合作用建立控制热膨胀的多种途径。化学修饰已被证明是控制热膨胀的有效方法。最后，讨论了 NTE 材料发展面临的挑战和问题。对于化学家来说，为每个特定应用发现“完美”的 NTE 材料仍然是一个挑战。对 NTE 功能材料的未来研究肯定会促进 NTE 材料的发展。
