Structural, electronic, elastic and vibrational properties of BiAlO3: A first principles study

• The structural parameters, electronic structures, Born effective charge tensor, elastic and vibrational properties of the rhombohedral BiAlO3 were performed by means of the density functional theory within the LDA.
• Based on the elastic constants and their related parameters, the crystal mechanical stability have been discussed.
• Energy band structure shows that the rhombohedral BiAlO3 has an indirect band gap between D and Г-D symmetry points.
• We compute Born effective charge tensor, which is found to be quite anisotropic of Bi and O atoms.
• We have revealed the structure of the rhombohedral phase of frequencies of the zone-center model and the soft mode between X and Г high-symmetry points which is responsible for rhombohedral–cubic phase transition.

We present a study of the structural, electronic, elastic and vibrational properties of the rhombohedral BiAlO3 structure within the local density approximation of density functional theory using norm-conserving pseudopotentials. The calculated equilibrium lattice constant, angle and atomic position are in reasonable agreement with the available experimental and theoretical dates. Based on the elastic constants and their related parameters, the crystal mechanical stability have been discussed. The elastic constants for BiAlO3 are also needed to completely determine its elastic properties including polycrystalline bulk, shear and Young’s moduli, Poisson’s ratio and the elastic anisotropy. Energy band structure shows that the rhombohedral BiAlO3 has an indirect band gap between D and Г-D symmetry points. We compute Born effective charge tensor, which is found to be quite anisotropic of Bi and O atoms. BiAlO3 have been studied by applying the direct method and deriving the phonon dispersion relations which include the longitudinal/transverse optical phonon mode splitting. In the rhombohedral phase the phonon dispersion curves show a soft mode between X and Г-point. This soft mode leads to the observed rhombohedral-cubic phase transition. The results are compared with the previous calculations and available experimental data.