Optical anisotropy in bismuth titanate: An experimental and theoretical study

Abstract

We report experimental and theoretical investigation of anisotropy in optical properties and their origin in the ferroelectric and paraelectric phases of bismuth titanate. Room temperature ellipsometric measurements performed on pulsed laser deposited bismuth titanate thin films of different orientations show anisotropy in the dielectric and optical contstants, Subsequent first-principles calculations performed on the ground state structures of ferroelectric and high temperature paraelectric phases of bismuth titanate show that the material demonstrates anisotropic optical behavior in both ferroelectric and paraelectric phases. We further show that O 2p to Ti 3d transition is the primary origin of optical activity of the material while optical anisotropy results from the asymmetrically oriented Ti-O bonds in TiO 6 octehdra in the unit cell.

Potassium titanyl phosphate (KTP) quasiparticle energies and optical response

“…However, the anisotropy between xx/yy and zz remains, since the density of TiO 6 octahedra along the respective directions differs. Similar observations were made earlier for bismuth titanate (Bi 4 Ti 3 O 12 ) [44].…”

Origin of the optical anisotropy and the electronic structure of Ru-based double perovskite oxides: DFT and XPS studies

“…29 Thus, it is plausible that the orientation differences among the RuO 6 octahedra lead to the different transition behaviour from O 2p to Ru 4d states, which is the primary factor responsible for the optical activity of A 2 LiRuO 6 compounds, rendering anisotropic optical behaviour. 30 4.4. X-ray photoemission spectroscopy study Fig.…”