Effect of substituting of S for O: The sulfide perovskite BaZrS3 investigated with density functional theory

We use first-principles density functional theory calculations to investigate the ground-state structure of sulfide perovskite BaZrS3. The material has a lower band gap than its oxide analog BaZrO3. Neither are ferroelectric in the ground state at T=0 K. We also examine the IR-active phonon contributions to the dielectric constant of BaZrS3, which are then compared to those of BaZrO3. The roles of atomic size, mass, and covalency are discussed with regard to band gap and dielectric response.