Ab initio calculations of elastic modulus and electronic structures of cubic CaZrO3

Using the plane wave pseudopotential method within the generalized gradient approximation (GGA), we have studied the elastic constants and electronic structures of CaZrO3 crystallized in cubic perovskite structure. The independent elastic constants of cubic CaZrO3, which are derived by calculating the strain-induced stresses, satisfy the requirement of mechanical stability and indicate cubic CaZrO3 could be stable. It is found that cubic CaZrO3 is an indirect insulator with the GGA energy band gap of 3.30 eV. The bottom of conduction bands of cubic CaZrO3 is mainly contributed by Ca-3d states with some mixture of Zr-4d and Ca-4s states, while the top of valence bands is dominated by 0-2p states. The Zr-O bond has a significant covalent character while the Ca-O bond is typically ionic. (C) 2008 Elsevier B.V. All rights reserved.