Open AccessДинамика решетки и электронные свойства нелинейного кристалла BaGa-=SUB=-2-=/SUB=-GeS-=SUB=-6-=/SUB=-: комбинационное рассеяние, ИК отражение и расчет ab initio
Author(s) -
С. А. Климин,
Б. Н. Маврин,
I. V. Budkin,
Valeriy Badikov,
Dmitrii Badikov
Publication year - 2019
Publication title -
žurnal tehničeskoj fiziki
Language(s) - English
Resource type - Journals
eISSN - 1726-748X
pISSN - 0044-4642
DOI - 10.21883/os.2019.07.47925.66-19
Subject(s) - phonon , ab initio , raman spectroscopy , band gap , dispersion (optics) , raman scattering , crystal (programming language) , ab initio quantum chemistry methods , electronic band structure , spectral line , electronic structure , reflection (computer programming) , condensed matter physics , density functional theory , molecular physics , density of states , materials science , atomic physics , chemistry , physics , computational chemistry , optics , molecule , organic chemistry , astronomy , computer science , programming language
We have measured the polarized Raman scattering and IR reflection spectra of a BaGa_2GeS_6 crystal, the Ga and Ge atoms of which are disordered, randomly occupying crystallographic positions of the same kind. The IR reflection spectra have been processed by the dispersion analysis method. The dispersion of phonons, the density of phonon states, the electronic band structure, and the partial densities of electronic states have been calculated in the DFT approximation using the alchemical potential method for disordered Ga and Ge atoms. It has been found that the stretching vibrations in the vibrational spectra are separated from the bending modes by a gap of about 100 cm^–1 and that the band structure of the crystal has an indirect energy gap.