Unexpected Competition between Ferroelectricity and Rashba Effects in Epitaxially Strained SrTiO_{3}.

The Rashba parameter α_{R} is usually assumed to scale linearly with the amplitude of polar displacements by construction of the spin-orbit interaction. On the basis of first-principles simulations, ferroelectric phases of SrTiO_{3} reached under epitaxial compressive strain are characterized by (i) large Rashba effects at the bottom of the conduction band near the paraelectric-ferroelectric boundary and (ii) an unexpected suppression of the phenomena when the amplitude of polar displacements increases. This peculiar behavior is ascribed to the inverse dependence of the Rashba parameter with the crystal field Δ_{CF} induced by the polar displacements that alleviates the degeneracy of Ti t_{2g} states and annihilates the Rashba effects.

Origin of band gaps in 3d perovskite oxides.

With their broad range of properties, ABO transition metal perovskite oxides have long served as a platform for device applications and as a testing bed for different condensed matter theories. Their insulating character and structural distortions are often ascribed to dynamical electronic correlations within a universal, symmetry-conserving paradigm. This view restricts predictive theory to complex computational schemes, going beyond density functional theory (DFT).

Electrically Switchable and Tunable Rashba-Type Spin Splitting in Covalent Perovskite Oxides.

In transition-metal perovskites (ABO_{3}) most physical properties are tunable by structural parameters such as the rotation of the BO_{6} octahedra. Examples include the Néel temperature of orthoferrites, the conductivity of mixed-valence manganites, or the band gap of rare-earth scandates. Since oxides often hold large internal electric dipoles and can accommodate heavy elements, they also emerge as prime candidates to display Rashba spin-orbit coupling, through which charge and spin currents may be efficiently interconverted.

Chemical Strain Engineering of Magnetism in Oxide Thin Films.

Transition metal oxides having a perovskite structure form a wide and technologically important class of compounds. In these systems, ferroelectric, ferromagnetic, ferroelastic, or even orbital and charge orderings can develop and eventually coexist. These orderings can be tuned by external electric, magnetic, or stress field, and the cross-couplings between them enable important multifunctional properties, such as piezoelectricity, magneto-electricity, or magneto-elasticity.