Effect of symmetry lowering on the dielectric response of BaZrO 3

We use first-principles density functional theory calculations to investigate the dielectric response of BaZrO3 perovskite. A previous study [Akbarzadeh et al., Phys. Rev. B 72, 205104 (2005)] reported a disagreement between experimental and theoretical low temperature dielectric constant ϵ for the high symmetry BaZrO3 structure. We show that a fully relaxed 40 atom BaZrO3 structure exhibits O6 octahedral tilting, and ϵ that agrees with experiment. The change in ϵ from high-symmetry to low-symmetry structure is due to increased phonon frequencies as well as decreased mode effective charges.