First Principle Local Density Approximation Description of the Electronic Properties of Ferroelectric Sodium Nitrite

TL;DR

This study uses first-principles local density approximation calculations to accurately determine the electronic properties of ferroelectric NaNO₂, including band gaps and effective masses, aligning well with experimental data.

Contribution

It applies an enhanced BZW-EF method within LDA to precisely compute electronic structure parameters of NaNO₂, a ferroelectric material, demonstrating high localization and anisotropic electron effective masses.

Findings

Indirect band gap of 2.83 eV from W to R

Calculated direct gaps at various high-symmetry points

High localization and anisotropic effective masses

Abstract

The electronic structure of the ferroelectric crystal, NaNO$_2$, is studied by means of first-principles, local density calculations. Our ab-initio, non-relativistic calculations employed a local density functional approximation (LDA) potential and the linear combination of atomic orbitals (LCAO). Following the Bagayoko, Zhao, Williams, method, as enhanced by Ekuma, and Franklin (BZW-EF), we solved self-consistently both the Kohn-Sham equation and the equation giving the ground state charge density in terms of the wave functions of the occupied states. We found an indirect band gap of 2.83 eV, from W to R. Our calculated direct gaps are 2.90, 2.98, 3.02, 3.22, and 3.51 eV at R, W, X, {\Gamma}, and T, respectively. The band structure and density of states show high localization, typical of a molecular solid. The partial density of states shows that the valence bands are formed only by complex anionic states. These results are in excellent agreement with experiment. So are the calculated densities of states. Our calculated electron effective masses of 1.18, 0.63, and 0.73 mo in the {\Gamma}-X, {\Gamma}-R, and {\Gamma}-W directions, respectively, show the highly anisotropic nature of this material.