First-principles calculations of phonon derived Raman and infrared spectra in Be-IV-N2 compounds

Abstract

A first-principles study is presented of the phonons in Be-IV-N2 compounds, with IV = (Si,Ge). These compounds are closely related to wurtzite BN by replacing the group III (B) by group II (Be) and group IV (Si or Ge). The phonon frequencies at the Brillouin zone center are used to predict the corresponding infrared and Raman spectra. The phonon frequencies, oscillator strengths, Born effective charges, and dielectric constants on which these spectra are based are provided.