First-principles characterization of the four phases of barium titanate

Using a first-principles approach, the four phases of perovskite barium titanate are studied. We determine the lattice parameter, the bulk modulus and the cohesive energy of the cubic phase; the relaxed atomic positions in the three ferroelectric structures; and the evolution of the electronic properties from one phase to the other. The role of electronic exchange-correlation energy in the stabilization of the different phases is also investigated.