Electronic structure of cubic SrHfO₃: Ferroelectric stability and detailed comparison with SrTiO₃

Abstract

Electronic structure calculations of cubic SrTiO₃ and SrHfO₃ are presented. The full-potential linear augmented-plane-wave method is used and exchange-correlation effects are treated by the local-density approximation. The tendency to ferroelectricity of both compounds is explored and compared by displacing the transition metal atom (Ti or Hf) towards one of the oxygens (001 direction). The calculations show that ferroelectricity is favored in SrTiO₃ with respect to SrHfO₃ and that this fact may be correlated with the degree of hybridization between transition metal d-O p bands as has been found for other related systems. Also a detailed discussion of the calculated electric field gradients is presented.