Oxygen packaging in transition metal oxides determines the metal-oxygen hybridization and electronic occupation at metal orbitals. Strontium vanadate (SrVO3), having a single electron in a 3d orbital, is thought to be the simplest example of strongly correlated metallic oxides. Here, we determine the effects of epitaxial strain on the electronic properties of SrVO3 thin films, where the metal-oxide sublattice is corner connected.
Using x-ray absorption and x-ray linear dichroism at the VL2,3 and O K edges, it is observed that tensile or compressive epitaxial strain change the hierarchy of orbitals within the t2g and eg manifolds. Data show a remarkable 2p−3d hybridization, as well as a strain-induced reordering of the V3d(t2g,eg) orbitals. The latter is itself accompanied by a consequent change of hybridization that modulates the hybrid π∗ and σ∗ orbitals and the carrier population at the metal ions, challenging a rigid band picture.
Oxides for new-generation electronics
Orbital occupancy and hybridization in strained SrVO3 epitaxial films
Mathieu Mirjolet,*, Hari Babu Vasili, Adrian Valadkhani, José Santiso, Vladislav Borisov, Pierluigi Gargiani, Manuel Valvidares, Roser Valentí, and Josep Fontcuberta
When illuminating a non-centrosymmetric material with light of energy higher than the bandgap, a net current appears because the electrons do not see the same electronic environment in one direction and the opposite direction, thus they hold a net momentum. This is the bulk photovoltaic effect (BPE), which depends on the light polarization.
Spin-charge conversion requires materials with a large spin-orbit coupling, which is typically obtained in heavy metal (Pt, etc.) ions. Here we demonstrate spin pumping across interfaces between metallic SrVO3, where V is a 3d1 ion, epitaxial thin films and ferromagnetic Ni80Fe20.
Building on recent developments in electronic-structure methods, we define and calculate the flexoelectric response of two-dimensional (2D) materials fully from first principles. In particular, we show that the open-circuit voltage response to a flexural deformation is a fundamental linear-response property of the crystal that can be calculated within the primitive unit cell of the flat configuration.
We present a complete structural study of the successive phase transitions observed in the YBaMn2O6 compound with the layered ordering of cations on the perovskite A-site. We have combined synchrotron radiation X-ray powder diffraction and symmetry-adapted mode analysis to describe the distorted structures as pseudosymmetric with respect to the parent tetragonal structure.
The development of new synthetic methodologies of perovskite oxynitrides is challenging but necessary for the search of new compounds and the investigation of new properties. Here, we report a new method of preparation of the perovskite LaTaON2 that has been investigated as a pigment and photocatalyst for water splitting.