## 抄録

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 BaTiO_{3}, PbTiO_{3}, 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.

本文言語 | English |
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論文番号 | 134106 |

ジャーナル | Physical Review B - Condensed Matter and Materials Physics |

巻 | 82 |

号 | 13 |

DOI | |

出版ステータス | Published - 2010 10月 6 |

## ASJC Scopus subject areas

- 電子材料、光学材料、および磁性材料
- 凝縮系物理学

## フィンガープリント

「First-principles accurate total energy surfaces for polar structural distortions of BaTiO_{3}, PbTiO

_{3}, and SrTiO

_{3}: Consequences for structural transition temperatures」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。