The Effect of Symmetry Lowering on the Dielectric Response of
arXiv:cond-mat/0603674 · doi:10.1103/PhysRevB.73.180102
Abstract
We use first-principles density functional theory calculations to investigate the dielectric response of BaZrO perovskite. A previous study [Arkbarzadeh {\em et al.} Phys. Rev. B {\bf 72}, 205104 (2005)] reported a disagreement between experimental and theoretical low temperature dielectric constant for the high symmetry BaZrO structure. We show that a fully relaxed 40-atom BaZrO structure exhibits O octahedral tilting, and that agrees with experiment. The change in from high-symmetry to low-symmetry structure is due to increased phonon frequencies as well as decreased mode effective charges.
4 pages, 2 figures