TY - JOUR

T1 - First-principles accurate total energy surfaces for polar structural distortions of BaTiO3, PbTiO3, and SrTiO3

T2 - Consequences for structural transition temperatures

AU - Nishimatsu, Takeshi

AU - Iwamoto, Masaya

AU - Kawazoe, Yoshiyuki

AU - Waghmare, Umesh V.

PY - 2010/10/6

Y1 - 2010/10/6

N2 - Specific forms of the exchange-correlation energy functionals in first-principles density-functional-theory-based calculations, such as the local-density approximation (LDA) and generalized-gradient approximations (GGA), give rise to structural lattice parameters with typical errors of -2% and 2%. Due to a strong coupling between structure and polarization, the order parameter of ferroelectric transitions, they result in large errors in estimation of temperature-dependent ferroelectric structural transition properties. Here, we employ a recently developed GGA functional of Wu and Cohen [Phys. Rev. B 73, 235116 (2006)]10.1103/PhysRevB.73.235116 and determine total energy surfaces for zone-center distortions of BaTiO3, PbTiO3, and SrTiO 3 and compare them with the ones obtained with calculations based on standard LDA and GGA. Confirming that the Wu and Cohen functional allows better estimation of structural properties at 0 K, we determine a set of parameters defining the effective Hamiltonian for ferroelectric transition in BaTiO 3. Using the new set of parameters, we perform molecular-dynamics simulations under effective pressures p=0.0 GPa, p=-2.0 GPa, and p=-0.005T GPa. The simulations under p=-0.005T GPa, which is for simulating thermal expansion, show a clear improvement in the cubic to tetragonal transition temperature and c/a parameter of its ferroelectric tetragonal phase, while the description of transitions at lower temperatures to orthorhombic and rhombohedral phases is marginally improved. Our findings augur well for use of Wu-Cohen functional in studies of ferroelectrics at nanoscale, particularly in the form of epitaxial films where the properties depend crucially on the lattice mismatch.

AB - Specific forms of the exchange-correlation energy functionals in first-principles density-functional-theory-based calculations, such as the local-density approximation (LDA) and generalized-gradient approximations (GGA), give rise to structural lattice parameters with typical errors of -2% and 2%. Due to a strong coupling between structure and polarization, the order parameter of ferroelectric transitions, they result in large errors in estimation of temperature-dependent ferroelectric structural transition properties. Here, we employ a recently developed GGA functional of Wu and Cohen [Phys. Rev. B 73, 235116 (2006)]10.1103/PhysRevB.73.235116 and determine total energy surfaces for zone-center distortions of BaTiO3, PbTiO3, and SrTiO 3 and compare them with the ones obtained with calculations based on standard LDA and GGA. Confirming that the Wu and Cohen functional allows better estimation of structural properties at 0 K, we determine a set of parameters defining the effective Hamiltonian for ferroelectric transition in BaTiO 3. Using the new set of parameters, we perform molecular-dynamics simulations under effective pressures p=0.0 GPa, p=-2.0 GPa, and p=-0.005T GPa. The simulations under p=-0.005T GPa, which is for simulating thermal expansion, show a clear improvement in the cubic to tetragonal transition temperature and c/a parameter of its ferroelectric tetragonal phase, while the description of transitions at lower temperatures to orthorhombic and rhombohedral phases is marginally improved. Our findings augur well for use of Wu-Cohen functional in studies of ferroelectrics at nanoscale, particularly in the form of epitaxial films where the properties depend crucially on the lattice mismatch.

UR - http://www.scopus.com/inward/record.url?scp=78049364781&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=78049364781&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.82.134106

DO - 10.1103/PhysRevB.82.134106

M3 - Article

AN - SCOPUS:78049364781

VL - 82

JO - Physical Review B - Condensed Matter and Materials Physics

JF - Physical Review B - Condensed Matter and Materials Physics

SN - 0163-1829

IS - 13

M1 - 134106

ER -