First-principles study on the optical properties of NaNO2 in the ferroelectric and paraelectric phase

The full potential linearized augmented plane wave method within the generalized gradient approximation was used to calculate the optical properties of NaNO2. In order to understand the difference of optical properties between the ferroelectric and paraelectric phase, the imaginary part of dielectric function ε2(ω), the optical absorption coefficient I(ω) and the reflectivity R(ω) were calculated. The behavior of ε2(ω), I(ω) and R(ω) show that the ferroelectric NaNO2 is a very anisotropic material and the optical properties in the ferroelectric phase have a higher anisotropy than those in the paraelectric phase.