Effect of bond on negative thermal expansion of Prussian blue analogues MCo(CN)6(M = Fe, Ti and Sc): a first-principles study

Yuan Li; Qilong Gao; Dahu Chang; Pengju Sun; Junzhe Liu; Yu Jia; Erjun Liang; Qiang Sun

doi:10.1088/1361-648X/aba777

Effect of bond on negative thermal expansion of Prussian blue analogues MCo(CN)₆(M = Fe, Ti and Sc): a first-principles study

J Phys Condens Matter. 2020 Aug 13;32(45). doi: 10.1088/1361-648X/aba777.

Authors

Yuan Li¹, Qilong Gao¹, Dahu Chang², Pengju Sun¹, Junzhe Liu¹, Yu Jia^{1

3}, Erjun Liang¹, Qiang Sun¹

Affiliations

¹ Key Laboratory of Materials Physics , Ministry of Education International Laboratory for Quantum Functional Materials of Henan, School of Physics and Microelectronics, Zhengzhou University, Zhengzhou 450001, People's Republic of China.
² Department of Mathematics and Physics, Luoyang Institute of Science and Technology, Luoyang 471023, People's Republic of China.
³ Key Laboratory for Special Functional Materials of Ministry of Education, and School of Materials and Engineering, Henan University, Kaifeng, 475001, People's Republic of China.

PMID: 32688349
DOI: 10.1088/1361-648X/aba777

Abstract

Negative thermal expansion (NTE) is an abnormal physical behavior that has promising applications for high precision thermal control. Since Prussian blue analogues have the two central linking atoms of -C≡N-, they have large structure flexibility and are suitable to explore new NTE materials. However, understanding the nature of structure flexibility from the point of view of chemical bonding is important and urgent. Here, we adopt for the first time first-principles calculations to predict that the cubic TiCo(CN)₆and ScCo(CN)₆have NTE behavior. The calculated results for M in MCo(CN)₆(M = Fe, Ti and Co) indicated that the Sc-N bond is the strongest, but with the weakest direction dependence among the M-N bonds in the three systems. The lattice dynamics calculations results revealed that the low-frequency phonon vibration modes for NTE in MCo(CN)₆have much stronger relationship with the M-N bond feature. The present work reveals the important role of the related bond in the NTE open-framework materials.

Keywords: Prussian blue analogues; first-principles calculation; lattice dynamics; negative thermal expansion; phonon.