Chen Xin, Gao Qilong, Zhao Kaiyue, Qiao Yongqiang, Sanson Andrea, Sun Qiang, Guo Juan, Kawaguchi Shogo, Liang Erjun, Chen Jun
Key Laboratory of Materials Physics of Ministry of Education, School of Physics, Zhengzhou University Zhengzhou 450001 China
Department of Physics and Astronomy, Department of Management and Engineering, University of Padua Padova I-35131 Italy.
Chem Sci. 2025 Aug 7;16(35):16331-16338. doi: 10.1039/d5sc03604f. eCollection 2025 Sep 10.
The precise regulation of thermal expansion is a crucial and challenging topic with significant industrial and technological implications. We propose a charge interaction index (CII) to relate thermal expansion to chemical composition. Using AMO compounds as a case study, we show the validity of this parameter through experimental verification. Through first principles calculations, the charge density, potential well curves, and Grüneisen parameters of AMoO (where A = Al, Sc, and Y) were extracted. These calculations revealed that the CII value correlates strongly with the transverse thermal vibrations of bridging O atoms and, in turn, the low-frequency phonon modes possessing negative Grüneisen parameters. Three representative component designs, Sc(MgTi)MoO, InMoWO, and (AlScFeGaCr)WO, were synthetized. As predicted, synchrotron XRD as a function of temperature showed that InMoWO, which has the minimum CII value, exhibits negative thermal expansion behavior, while (AlScFeGaCr)WO, with the maximum CII value, displays positive thermal expansion. This work establishes a simple and effective strategy to engineer thermal expansion properties in open-framework materials through the CII idea.
热膨胀的精确调控是一个至关重要且具有挑战性的课题，具有重大的工业和技术意义。我们提出了一种电荷相互作用指数（CII），将热膨胀与化学成分联系起来。以AMO化合物为例，我们通过实验验证展示了该参数的有效性。通过第一性原理计算，提取了AMoO（其中A = Al、Sc和Y）的电荷密度、势阱曲线和格林艾森参数。这些计算表明，CII值与桥连O原子的横向热振动密切相关，进而与具有负格林艾森参数的低频声子模式相关。合成了三种代表性的组分设计，即Sc(MgTi)MoO、InMoWO和(AlScFeGaCr)WO。正如预测的那样，同步加速器XRD随温度的变化表明，具有最小CII值的InMoWO表现出负热膨胀行为，而具有最大CII值的(AlScFeGaCr)WO则表现出正热膨胀。这项工作通过CII理念建立了一种简单有效的策略，用于设计开放框架材料的热膨胀性能。
