Electronic properties of NaCdF₃: A first-principles prediction

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 ≈60meV lower than the sum of those of the constituents, NaF and CdF₂, implying chemical stability.