First-principles investigation of the physical properties of cubic and orthorhombic phase Na3UO4

The anisotropic elastic properties, Vickers hardness, Debye temperature and the minimum thermal conductivity of c-Na3UO4 and o-Na3UO4 have been investigated by means of the first principles calculations. The lattice parameters are in good agreement with the available experimental data and the theoretical results. The elastic constants satisfy the mechanical stability criteria show that both of them are mechanically stable. The value of B/G and Cauchy pressure reveal that the c-Na3UO4 holds a ductile behavior while the o-Na3UO4 behaves a brittle manner. The elastic anisotropy of c-Na3UO4 is less weak than that of o-Na3UO4. The hardness shows that both of them can be classified as “soft materials”. Finally, the Debye temperature is 452.6 K and 388.4 K, and the minimum thermal conductivities kmin is 0.883 W m−1 K−1 and 0.753 W m−1 K−1 of c-Na3UO4 and o-Na3UO4, respectively. Due to relatively lower thermal conductivity, and thereby they are suitable to be used as thermal insulating materials.