First-principles study of PbTiO${}_3$ under uniaxial strains and stresses

Abstract

The behavior of PbTiO${}_3$ under uniaxial strains and stresses is investigated from first-principles calculations within density functional theory. We show that irrespectively of the uniaxial mechanical constraint applied, the system keeps a purely ferroelectric ground-state, with the polarization aligned either along the constraint direction ($F{E}_z$ phase) or along one of the pseudo-cubic axis perpendicular to it ($F{E}_x$ phase). This contrasts with the cases of isotropic or biaxial mechanical constraints for which novel phases combining ferroelectic and antiferrodistortive motions have been previously reported. Under uniaxial strain, PbTiO${}_3$ switched from a $F{E}_x$ ground state under compressive strain to $F{E}_z$ ground-state under tensile strain, beyond a critical strain ${\eta }_{zz}^c\approx +1$\%. Under uniaxial stress, PbTiO${}_3$ exhibits either a $F{E}_x$ ground state under compression (${\sigma }_{zz}<0$) or a $F{E}_z$ ground state under tension (${\sigma }_{zz}>0$). Here, however, an abrupt jump of the structural parameters is also predicted under both compressive and tensile stresses at critical values ${\sigma }_{zz}\approx$ $+2$ GPa and $-8$ GPa. This behavior appears similar to that predicted under negative isotropic pressure and might reveal practically useful to enhance the piezoelectric response in nanodevices.

Submitted, 9 pages, 9 figures

References in corpus (2)

• Engineering multiferroism in CaMnO${}_3$
• The Magnetoelectric Effect in Transition Metal Oxides: Insights and the Rational Design of New Materials from First Principles

Cited by in corpus (4)

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• Ferroelectric control of spin-polarized two-dimensional electron gas
• Stability of the tetragonal phase of BaZrO3 under high pressure
• Ferroelectric Properties and Topological Polar Textures of PbTiO${}_3$ from a Second-Principles Open-Source Interatomic Potential