Understanding Large Negative Thermal Expansion of NdFe(CN)6 through the Electronic Structure and Lattice Dynamics

A large negative thermal expansion (NTE) (alpha v=-4.1x10-5K-1, 100-525 K) has been discovered in NdFe(CN)6.Here, the synchrotron X-ray diffraction and lattice dynamics calculations using the density functional theory were conducted tounderstand the NTE in NdFe(CN)6. The information obtained on the bond nature of the Nd-N???C-Fe linkage and on the atomicthermal vibrations suggests that the transverse vibrations of the-N???C-group, in particular from N atoms, produced the NTE inNdFe(CN)6. This is corroborated by the calculated Gru??neisen parameters, which confirm the relationship between NTE and CNatomic vibrations. The results provide a helpful contribution toward the realization of new materials with negative or controllablethermal expansion

Automated summary

This study reveals that the negative thermal expansion in NdFe(CN)6 is mainly attributed to the vibrations of N atoms in its molecular structure, as confirmed by experimental and computational results.