Jiao Yixin, Gao Qilong, Sanson Andrea, Liang Erjun, Sun Qiang, Chen Jun
Key Laboratory of Materials Physics of Ministry of Education, and School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450052, China.
Department of Physics and Astronomy, University of Padova, Padova I-35131, Italy.
Inorg Chem. 2022 May 23;61(20):7813-7819. doi: 10.1021/acs.inorgchem.2c00310. Epub 2022 May 11.
A large negative thermal expansion (NTE) (α = -4.1 × 10 K, 100-525 K) has been discovered in NdFe(CN). Here, the synchrotron X-ray diffraction and lattice dynamics calculations using the density functional theory were conducted to understand the NTE in NdFe(CN). The information obtained on the bond nature of the Nd-N≡C-Fe linkage and on the atomic thermal vibrations suggests that the transverse vibrations of the -N≡C- group, in particular from N atoms, produced the NTE in NdFe(CN). This is corroborated by the calculated Grüneisen parameters, which confirm the relationship between NTE and CN atomic vibrations. The results provide a helpful contribution toward the realization of new materials with negative or controllable thermal expansion.
在钕铁氰化物（NdFe(CN)）中发现了大的负热膨胀（NTE）（α = -4.1 × 10⁻⁶ K⁻¹，100 - 525 K）。在此，利用密度泛函理论进行了同步加速器X射线衍射和晶格动力学计算，以了解钕铁氰化物中的NTE。关于Nd-N≡C-Fe键合性质和原子热振动所获得的信息表明，-N≡C-基团的横向振动，特别是来自N原子的振动，在钕铁氰化物中产生了NTE。计算得到的格林艾森参数证实了这一点，其确认了NTE与C≡N原子振动之间的关系。这些结果为实现具有负热膨胀或可控热膨胀的新材料做出了有益贡献。
