Based on first-principles total energy calculations, we predict that NaCdF3 could be formed in a ferroelectric crystal structure. Using a symmetry guided search with structure optimization, we found two ferroelectric structures, nearly degenerate in energy, competing for the ground state: a rhombohedral structure with space group R3c and an orthorhombic structure with space group Pna21. The energies of both structures are '60 meV lower than the sum of those of the constituents, NaF and CdF2, implying chemical stability.
Duan, Chun-Gang; Mei, Wai-Ning; Liu, Jianjun; Yin, Wei-Guo; Hardy, John R.; Smith, Robert W.; Mehl, M. J.; and Boyer, L. L., "Electronic Properties of NaCdF3: A First-Principles Prediction" (2004). Physics Faculty Publications. 13.