The Rashba effect plays important roles in emerging quantum materials physics and potential spintronic applications, entailing both the spin orbit interaction (SOI) and broken inversion symmetry. In this work, we devise asymmetric oxide heterostructures of LaAlO₃//SrTiO₃/LaAlO₃ (LAO//STO/LAO) to study the Rashba effect in STO with an initial centrosymmetric structure, and broken inversion symmetry is created by the inequivalent bottom and top interfaces due to their opposite polar discontinuities. Furthermore, we report the observation of a transition from the cubic Rashba effect to the coexistence of linear and cubic Rashba effects in the oxide heterostructures, which is controlled by the filling of Ti orbitals. Such asymmetric oxide heterostructures with initially centrosymmetric materials provide a general strategy for tuning the Rashba SOI in artificial quantum materials.

The effect of biaxial strain on the oxygen octahedra rotations in a LaVO3 thin film is investigated using synchrotron radiation. First, we find that the film adopts a distorted orthorhombic structure under the compressive stress induced by the SrTiO3 substrate. Second, we separate the contribution to the superstructure peaks arising from cation displacement and VO6 rotations in order to quantify the rotation angles. Finally, we find an original a$-${}a+c$-${} tilt system, which is induced by the biaxial strain imposed by the substrate. These quantitative results may open up new directions for understanding the modification of electronic properties of engineered oxide films.

A series of epitaxial ${\left(\mathrm{La}\mathrm{V}{\mathrm{O}}_3\right)}_{6m}{\left(\mathrm{Sr}\mathrm{V}{\mathrm{O}}_3\right)}_m$ superlattices having the same nominal composition as ${\mathrm{La}}_{6∕7}{\mathrm{Sr}}_{1∕7}\mathrm{V}{\mathrm{O}}_3$ , a Mott-Hubbard insulator, was grown with pulsed-laser deposition on [001]-oriented $\mathrm{Sr}\mathrm{Ti}{\mathrm{O}}_3$ substrates, and their superlattice period was varied. When $m=1$ , the insulating resistivity of bulklike ${\mathrm{La}}_{6∕7}{\mathrm{Sr}}_{1∕7}\mathrm{V}{\mathrm{O}}_3$ is obtained; however, an increase in the periodicity $(m⩾2)$ results in metallic samples. Comparison of the superlattice periodicity with the coherence length of charge carriers in perovskite oxide heterostructures is used to understand these observations. A filling-controlled insulator-metal transition was induced by placing a single dopant layer of $\mathrm{Sr}\mathrm{V}{\mathrm{O}}_3$ within $\mathrm{La}\mathrm{V}{\mathrm{O}}_3$ layers of varying thickness.

Transition-metal oxides with an ${\text{ABO}}_3$ perovskite structure exhibit strongly entangled structural and electronic degrees of freedom and thus one expects to unveil exotic phases and properties by acting on the lattice through various external stimuli. Using the Jahn-Teller active praseodymium vanadate ${\mathrm{Pr}}^{3+}{\mathrm{V}}^{3+}{\mathrm{O}}_3$ compound as a model system, we show that ${\mathrm{PrVO}}_3$ Néel temperature $T_N$ can be raised by 40 K with respect to the bulk when grown as thin films. Using advanced experimental techniques, this enhancement is unambiguously ascribed to a tetragonality resulting from the epitaxial compressive strain experienced by the films. First-principles simulations not only confirm experimental results, but they also reveal that the strain promotes an unprecedented orbital ordering of the ${\mathrm{V}}^{3+}d$ electrons, strongly favoring antiferromagnetic interactions. These results show that an accurate control of structural aspects of oxides is the key for unveiling unexpected phases in oxides.