First-principles study of piezoelectricity in tetragonalPbTiO3andPbZr1/2<

Density functional theory study of hypotheticalPbTiO3-based oxysulfides

“…[40][41][42] The relaxed lattice parameters are a = 3.87Å and c = 4.07Å, yielding a c/a ratio of 1.05. We find an indirect (X-Γ) band gap of 1.47 eV and polarization (strictly in the z direction) of 0.85 C/m 2 .…”

Origin of the High Piezoelectric Response inPbZr1−xTixOGuo1, Cross2, Park3 et al. 2000Phys. Rev. Lett.1,018345464View full textAdd to dashboardCite

“…Experimental confirmation of this prediction was obtained [5,6,7] for the related ferroelectric relaxor system PbZn 1/3 Nb 2/3 -PbTiO 3 (PZN-PT), which has a rhombohedral-to-tetragonal MPB similar to that of PZT, but it has not been possible to verify similar behavior in PZT due to the lack of single crystals. Furthermore, ab initio calculations based on the assumption of tetragonal symmetry, that have been successful for calculating the piezoelectric properties of pure PbTiO 3 [8,9,10,11], were unable to account for the much larger piezoelectric response in PZT compositions close to the MPB. Thus, it is clear that the current theoretical models lack some ingredient which is crucial to understanding the striking piezoelectric behavior of PZT.…”

Finite-Temperature Properties ofPb(Zr1−xTix)

“…On the one hand, semi-empirical simulations predict that the large experimental value of the d 33 piezoelectric coefficient results mainly from the large value of d 33 that a single-crystal PZT would exhibit [4]. On the other hand, recent firstprinciples calculations [5,6] have found that the d 33 coefficient of a tetragonal single crystal of Pb(Zr 0.5 Ti 0.5 )O 3 are estimated to be three times smaller than the experimental value obtained for ceramics at low temperature.Furthermore, recent synchrotron x-ray powder diffraction studies have revealed the existence of an unexpected low-temperature monoclinic phase of PZT at x=0.48 [7], which implies that the phase diagram of PZT is more complex than previously thought. This monoclinic phase may act as a second-order transitional bridge between the tetragonal phase, for which the electrical polarization P lies along the pseudo-cubic [001] direction, and the rhombohedral phase, for which P is along the pseudo-cubic [111] direction.…”