Abstract
The atomic and electronic structure, zone center phonon frequencies, and optical absorption of are calculated from first principles. The structural and vibrational properties predicted from density functional theory are in good agreement with experiment and earlier theoretical work. The electronic band-structure and optical properties are found to be very sensitive to quasiparticle and electron-hole attraction effects, which are included here using the approach and by solving the Bethe-Salpeter equation, respectively. We predict the fundamental gap to be more than larger than the frequently cited for ferrolectric and calculate optical absorption spectra in good agreement with experiment.
- Received 1 October 2007
DOI:https://doi.org/10.1103/PhysRevB.77.035106
©2008 American Physical Society