title: Competition and cooperation between antiferrodistortive and ferroelectric instabilities in the model perovskite SrTiO3.
abstract: We use density functional theory to explore the interplay between octahedral rotations and ferroelectricity in the model compound SrTiO3. We find that over the experimentally relevant range octahedral rotations suppress ferroelectricity as is generally assumed in the literature. Somewhat surprisingly, we observe that at larger angles the previously weakened ferroelectric instability strengthens significantly. By analyzing geometry changes, energetics, force constants and charges, we explain the mechanisms behind this transition from competition to cooperation with increasing octahedral rotation angle.
authors.affiliation: Materials Theory, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zürich, Switzerland.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Aschauer
authors.forename: Nicola A
authors.initials: NA
authors.lastname: Spaldin
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry*; D003198:Computer Simulation; D004574:Electromagnetic Fields; D008956:Models, Chemical; D008958:Models, Molecular; D010087:Oxides / Q000737:chemistry*; D012542:Scattering, Radiation; D013324:Strontium / Q000737:chemistry*; D014025:Titanium / Q000737:chemistry*
chemical_list: D017610:Calcium Compounds; D010087:Oxides; C059910:perovskite; D014025:Titanium; C119252:strontium titanium oxide; D013324:Strontium