Ab initio study of the effect of uniaxial pressure on the ferroelectric properties of PbTiO3

We have studied the effect of uniaxial pressure on the ferroelectric properties of PbTiO3 by using a first principles electronic structure method. The pressure is applied in the ab-plane. The magnitude of the ferroelectric lattice distortion is found to increase as the pressure is increased. Short Ti-O bonds along the c-direction are found to remain almost constant in length whereas the stretched Ti-O bonds become more stretched because of an increase in the equilibrium lattice constant in the c-direction. The thermodynamic stability of the ferroelectric phase over the paraelectric phase increases as pressure is applied.