We demonstrate a new band engineering strategy for the design of semiconductor perovskite ferroelectrics for photovoltaic and other applications from first principles. We study six ferroelectric solid solutions created by partially substituting Zn2+ for Nb5+ into the parent KNbO3 material, combined with charge compensation at the A sites with different combinations of higher valence cations. Ou...

We report density functional studies of electron rich interfaces between KTaO3 or KNbO3 and CaSnO3 or ZnSnO3 and in particular the nature of the interfacial electron gasses that can be formed. We find that depending on the details these may occur on either the transition metal or stannate sides of the interface and in the later case can be shifted away from the interface by ferroelectricity. We...

(1 − x)KNbO3–xBiMnO3 (0 ≤ x 0.25) ceramics were prepared by the solid-state reaction method. An X-ray diffraction analysis combined with Raman spectroscopy showed co-solubility of Bi and Mn in orthorhombic structure to be less than 5% BiMnO3. Orthorhombic pseudocubic symmetries coexist 0.05 0.15 region, coinciding a bimodal grain size distribution. This coexistence crystal is further corroborat...

Using an extension of a first-principles method developed by King-Smith and Vanderbilt Phys. Rev. B, 49, 5828 1994 , we investigate the effects of in-plane epitaxial strain on the ground-state structure and polarization of eight perovskite oxides: BaTiO3, SrTiO3, CaTiO3, KNbO3, NaNbO3, PbTiO3, PbZrO3, and BaZrO3. In addition, we investigate the effects of a nonzero normal stress. The results ar...

The potassium niobate (KNbO3) sample was hydrothermally synthesized using Nb2O5 and KOH solution as precursors. X-ray diffraction (XRD) results show that the KNbO3 is a single-phase material with an orthorhombic crystal structure unit cell parameters are: = 3.9743 (2) Å; b 5.6954 c 5.7229 ? ? ? 90°, V 129.54 (1) Å3. temperature-dependent phase transitions enthalpy changes of were investigated b...