Polarization calculations for ferroelectric sodium nitrite

Abstract

Energy bands were calculated for ferroelectric sodium nitrite using a plane-wave Gaussian basis set and an XI exchange. Wave functions were calculated at five symmetry k points, and the electron charge density was averaged over the five symmetry points. The electric dipole moment per unit molecule was calculated by assuming that the boundaries of a neutral molecule were given by minimum charge density contours. The spontaneous polarization for ferroelectric sodium nitrite calculated using the above assump tion was 9.9 x C/cm2 measured by Tokugawa.C/cm*. which agrees with the experimental value of 9.5 x

First principle local density approximation description of the electronic properties of ferroelectric sodium nitrite

“…The periodic Hatree-Fock (PHF) method of McCarthy [15] overestimated the gap by a factor of 2-3. Henkel et al [16] employed their plane-wave and Gaussian basis set and an Xα exchange and reported a direct band gap of 2.70 eV. These results suffice to see that theoretical calculations have not resolved the under-or overestimation of the band gap of ferroelectric NaNO 2 .…”