Wang Lei, Chen Ying, Miura Hideo, Suzuki Ken, Wang Cong
Department of Physics, University of Science and Technology Beijing Beijing 100083 China
Fracture and Reliability Research Institute, Graduate School of Engineering, Tohoku University Sendai 980-8579 Japan.
RSC Adv. 2022 Aug 8;12(34):21770-21779. doi: 10.1039/d2ra03292a. eCollection 2022 Aug 4.
This paper proposes that it will be an effective way to discover and explore organic negative thermal expansion (NTE) materials based on the specific topologies in inorganic NTE materials. Various NTE behaviors from the uniaxial, area, and volume-NTE can be achieved by adjusting the topology, for instance, quartz-like and diamond-like. Zn(ISN) and InH(BDC) metal-organic frameworks (MOFs) with quartz-like topology have been studied by first principles calculations. The calculated area-NTE of Zn(ISN) and uniaxial-NTE of InH(BDC) within quasi-harmonic approximation (QHA) agree well with the experimental data. Through the calculation of Grüneisen parameters, it is shown that low-frequency optical phonons appear dominant resulting in their NTE, but the coupling to high-frequency phonons is of greater ultimate importance. The lattice vibrational modes of great contribution to area-NTE of Zn(ISN) and uniaxial-NTE of InH(BDC) are analyzed in detail. Also, four MOFs with diamond-like topology are predicted to exhibit volume-NTE behavior. Moreover, it is found that there is a bulk modulus anomaly in some studied MOFs with the quartz-like and diamond-like framework, where the temperature dependence of bulk modulus does not follow the inverse dependence on that of volume. These specific topologies provide key geometric frameworks for various NTE behaviors of MOFs, and meanwhile, the local structure and bond environment in MOFs can lead to abnormal interatomic force, , bulk modulus anomaly. This abnormal elastic property also deserves more attention.
本文提出，基于无机负热膨胀（NTE）材料中的特定拓扑结构来发现和探索有机NTE材料将是一种有效的方法。通过调整拓扑结构，例如类石英和类金刚石拓扑结构，可以实现单轴、面积和体积NTE等各种NTE行为。采用第一性原理计算方法研究了具有类石英拓扑结构的Zn(ISN)和InH(BDC)金属有机框架（MOF）。在准谐近似（QHA）下计算得到的Zn(ISN)的面积NTE和InH(BDC)的单轴NTE与实验数据吻合良好。通过对格林艾森参数的计算表明，低频光学声子在其NTE中起主导作用，但与高频声子的耦合最终更为重要。详细分析了对Zn(ISN)的面积NTE和InH(BDC)的单轴NTE贡献较大的晶格振动模式。此外，预测了四种具有类金刚石拓扑结构的MOF表现出体积NTE行为。而且，发现在一些具有类石英和类金刚石骨架的研究MOF中存在体积模量异常，其中体积模量的温度依赖性并不遵循与体积的反比关系。这些特定的拓扑结构为MOF的各种NTE行为提供了关键的几何框架，同时，MOF中的局部结构和键环境会导致异常的原子间力，即体积模量异常。这种异常的弹性性质也值得更多关注。
