Systematic {\em ab initio} study of the phase diagram of epitaxially strained SrTiO${}_3$

Abstract

We use density-functional theory with the local-density approximation to study the structural and ferroelectric properties of SrTiO${}_3$ under misfit strains. Both the antiferrodistortive (AFD) and ferroelectric (FE) instabilities are considered. The rotation of the oxygen octahedra and the movement of the atoms are fully relaxed within the constraint of a fixed in-plane lattice constant. We find a rich misfit strain-induced phase transition sequence and is obtained only when the AFD distortion is taken into account. We also find that compressive misfit strains induce ferroelectricity in the tetragonal low temperature phase only whilst tensile strains induce ferroelectricity in the orthorhombic phases only. The calculated FE polarization for both the tetragonal and orthorhombic phases increases monotonically with the magnitude of the strains. The AFD rotation angle of the oxygen octahedra in the tetragonal phase increases dramatically as the misfit strain goes from the tensile to compressive strain region whilst it decreases slightly in the orthorhombic (FO4) phase. This reveals why the polarization in the epitaxially strained SrTiO${}_3$ would be larger when the tensile strain is applied, since the AFD distortion is found to reduce the FE instability and even to completely suppress it in the small strain region. Finally, our analysis of the average polar distortion and the charge density distribution suggests that both the Ti-O and Sr-O layers contribute significantly to the FE polarization.

References in corpus (6)

• First-principles study of epitaxial strain in perovskites
• Effect of quantum fluctuations on structural phase transitions in SrTiO_3 and BaTiO_3
• Ab initio study of the phase diagram of epitaxial BaTiO3
• Tunability of the dielectric response of epitaxially strained SrTiO3 from first principles
• First-principles study of ferroelectric and antiferrodistortive instabilities in tetragonal SrTiO3
• ab initio Study of Strain-Induced Ferroelectricity in SrTiO3

Cited by in corpus (7)

• Strain gradient induced polarization in SrTiO3 single crystals
• Structure and properties of functional oxide thin films: Insights from electronic-structure calculations
• Band Gap and Edge Engineering via Ferroic Distortion and Anisotropic Strain: The Case of SrTiO${}_3$
• Substrate coherency-driven octahedral rotations in perovskite oxide films
• First-principles modeling of strain in perovskite ferroelectric thin films
• Ferroelectricity in [111]-oriented epitaxially strained SrTiO${}_3$ from first principles
• Metastability effects in strained and stressed SrTiO3 films