Effect of symmetry lowering on the dielectric response of BaZrO3

We use first-principles density functional theory calculations to investigate the dielectric response of BaZrO3 perovskite. A previous study [Akbarzadeh , Phys. Rev. B 72, 205104 (2005)] reported a disagreement between experimental and theoretical low temperature dielectric constant epsilon for the high symmetry BaZrO3 structure. We show that a fully relaxed 40 atom BaZrO3 structure exhibits O-6 octahedral tilting, and epsilon that agrees with experiment. The change in epsilon from high-symmetry to low-symmetry structure is due to increased phonon frequencies as well as decreased mode effective charges.