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Oxides for new-generation electronics

Water-Induced Phase Separation forming Macrostructured Epitaxial Quartz Films on Silicon



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  • Exact Long-Range Dielectric Screening and Interatomic Force Constants in Quasi-Two-Dimensional Crystals

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    26 November 2021 66 hit(s) Oxides
    Electrons in insulating crystals polarize in response to an externally applied electric field, resulting in a partial suppression of the field amplitude; such a phenomenon is known as “dielectric screening.” While much effort has gone into developing a quantitative understanding of this behavior and its impact on materials properties, 2D crystals remain challenging to describe by means of established modeling strategies.
  • Strong strain gradients and phase coexistence at the metal-insulator transition in VO2 epitaxial films

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    23 November 2021 66 hit(s) Oxides
    The proximity of a thermodynamic triple point and the formation of transient metastable phases may result in complex phase and microstructural trajectories across the metal-insulator transition in strained VO2 films. A detailed analysis using in-situ synchrotron X-ray diffraction unveils subtle fingerprints of this complexity in the structure of epitaxial films. During phase transition the low-temperature monoclinic M1 phase is constrained along the R planes by the coexisting high-temperature R phase domains, which remain epitaxially clamped to the substrate.
  • Positive Effect of Parasitic Monoclinic Phase of Hf0.5Zr0.5O2 on Ferroelectric Endurance

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    16 November 2021 192 hit(s) Oxides
    Endurance of ferroelectric HfO2 needs to be enhanced for its use in commercial memories. This work investigates fatigue in epitaxial Hf0.5Zr0.5O2 (HZO) instead of polycrystalline samples. Using different substrates, the relative amount of orthorhombic (ferroelectric) and monoclinic (paraelectric) phases is controlled. Epitaxial HZO films almost free of parasitic monoclinic phase suffer severe fatigue. In contrast, fatigue is mitigated in films with a greater amount of paraelectric phase.
  • Determination of the Crystal Structures in the A-Site-Ordered YBaMn2O6 Perovskite

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    12 November 2021 171 hit(s) Oxides
    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 YBaMn2O6 compound shows three consecutive phase transitions on cooling from 603 K down to 100 K. It undergoes a first-order structural transition at T1 ≈ 512 K from a C2/m cell with a single Mn site to a P21/c cell with two nonequivalent Mn sites.
  • Orbital occupancy and hybridization in strained SrV O 3 epitaxial films

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    05 November 2021 222 hit(s) Oxides
    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.

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