First-Principles Study of the Optical Properties of PbTiO3

The optical properties of PbTiO3 were studied by first principles using the density functional theory. The dielectric functions and optical constants are calculated using the full potential-linearized augmented plane wave (FP-LAPW) method with the generalized gradient approximation (GGA). The theoretically calculated optical properties and energy loss (EEL) spectrum yield a static refractive index of 2.83 and a plasmon energy of 23.1 eV for the cubic phase. The effective electron number at low energy saturates near 30 eVwith the value of 18.1 for the effective electron number. In the tetragonal phase the static refractive index decreases to 2.59 and yields a plasmon energy of 22.7 eV.