شبيه سازي ويژگي هاي الكترونيكي فاز فروالكتريك تيتانات سرب

Simulation of Electronic Properties of Ferroelectric Phase of PbTiO3

In this paper we have studied theoretically the structural and electronic properties of PbTiO3 in tetragonal phases. In this work we have used full potential linearized augmented plane waves in the framework of density functional theory and by local density approximation (LDA), generalized gradient approximation (GGA) , Engle Vosko (EVA) and GGA+U. The results of calculations for tetragonal phases of PbTiO3 show that there is a direct band gap in X direction in the first brillouin zone. The results of calculation for LDA , GGA and EV method give the band gap about 2-2.3 eV that it is not in agreement with experimental results but by the GGA+U we have calculated band gap about 3.5 eV which is in excellent agreement with experiment. Electronic density around each atom (Ti, Pb and O) have been calculated.