Effect of Mn Incorporated into LiNbO₃ Crystal Structure on the Electronic and Optical Properties Using First-Principles Study

Abstract

The structural, electronic and optical properties of lithium niobate (LiNbO3) and manganese (Mn)-doped LiNbO3 are investigated using a first-principles study. The first-principles calculation in this work is implemented using CASTEP computer code with GGA-PBE correlation. The band structure and density of states are calculated to analyze the effect of Mn doping on the electronic properties of LiNbO3. Hubbard U correction is applied to Nb 4d state with U= 11 eV and the corrected band gap obtained is 3.771 eV. LiNbO3 doped with Mn shows a reduction in the band gap energy which is 1.9889 eV. The dielectric constant and refractive index of LiNbO3 and Mn-doped LiNbO3 are also calculated. The optical absorption results suggest there is a shift in the absorption edge towards the visible region in comparison with the LiNbO3. The improvement in band gap and optical absorption in Mn-doped LiNbO3 making it a promising material for photovoltaic and photocatalysis applications.