SPONTANEOUS POLARIZATION AND ITS STRAIN EFFECTS FOR ORTHORHOMBIC AND MONOCLINIC Bi4Ti3O12: A FIRST PRINCIPLES STUDY

Abstract

Spontaneous polarization and its strain effects of bismuth titanate (BiT) with B2cb and B1a1 space groups are studied by first-principles density functional theory (DFT) calculation. B1a1 was proved to be the most stable phase structure and the spontaneous polarization is in good agreement with the experimental value. Similar variations of the principal polarization component (Pa) are obtained for B2cb and B1a1 structured BiT by applying b-uniaxial, c-uniaxial, ab-biaxial and bc-biaxial strains. It is found that the Pa is enhanced about 18.5% (20.8%) with ab-biaxial tensile strain of 2.4% for B2cb(B1a1) structure. Polarization along the c-axis (Pc) for the B1a1 structure is improved by 59.1% when bc-biaxial tensile strain reaches 2.4%.