Electronic structure, electronic charge density and optical properties analyses of Rb₂Al₂B₂O₇ compound: DFT

Abstract

We have presented an analysis of some important electronic and optical characteristics of the Rb₂Al₂B₂O₇ compound, based on the ab initio calculations of its electronic band structure, electronic charge density and dielectric tensor function. The band gap is found to be indirect of about 4.156, 4.471 and 5.205 eV for LDA, GGA and EVGGA respectively. The contributions to the top of valence band and bottom of conduction band come predominantly from O s/p, Al s/p and Rb s/p states, respectively. The distribution of the total electronic charge density maps (in the units of e/a.u.3) has been calculated along the (101) plane. The optical absorption spectrum is calculated and interpreted in terms of electronic band structure for incident radiation energy up to 14 eV. The principal absorption occurs within the energy range from 6.0 to 14.0 eV, originating mainly from the electronic transitions from the O-s to Al-s/p states. The complex dielectric function, refractive index, birefringence, energy-loss spectrum and reflectivity have been calculated.