Account of the self-interaction energy correction in the first principles calculation of the fundamental absorption edge spectrum of LiCl

TL;DR

This paper introduces an ab-initio method within local electron density functional theory that incorporates self-interaction correction to accurately calculate the fundamental absorption edge spectrum of LiCl, aligning well with experimental data.

Contribution

The paper presents a novel SIC scheme for the crystal potential in first-principles calculations, improving the accuracy of absorption edge spectra without fitting parameters.

Findings

Calculated spectra match experimental peak positions and shapes above 2.5 eV.

Interband transitions primarily determine the spectral features in this region.

Electron-hole interactions are crucial near the absorption edge for accurate spectrum modeling.

Abstract

Within the framework of the local electron density functional theory, an ab-initio method is proposed that takes into account the self-interaction energy correction (SIC) for the crystal potential. The principle of dividing the unit cell into regions remained the same as for the ground-state potential. The expression for the self-consistent muffin-tin-SIC potential satisfies the condition of cell electroneutrality. This scheme was applied to calculate the spectrum of the fundamental absorption edge of LiCl. The obtained interband transition energies were not required for fitting to experimental values. In the calculated spectrum, the shape and position of the peaks above ~2.5 eV from the edge agree fairly well with the measured ones, which allows their intensity in this region to be attributed primarily to interband transitions. Closer to the edge, electron-hole interaction significantly alters the ground state, which must be taken into account when calculating the spectrum shape.