A5083180277- High-pressure geophysics and materials
- Crystal Structures and Properties
- Chalcogenide Semiconductor Thin Films
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Solid-state spectroscopy and crystallography
- Luminescence Properties of Advanced Materials
- X-ray Diffraction in Crystallography
- Atmospheric Ozone and Climate
- Inorganic Chemistry and Materials
- Nuclear materials and radiation effects
- Electronic and Structural Properties of Oxides
- Topological Materials and Phenomena
- Rare-earth and actinide compounds
- Advanced Condensed Matter Physics
- Boron and Carbon Nanomaterials Research
- Quantum Dots Synthesis And Properties
- 2D Materials and Applications
- Zeolite Catalysis and Synthesis
- Spacecraft and Cryogenic Technologies
- Iron-based superconductors research
- ZnO doping and properties
- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Transition Metal Oxide Nanomaterials
Universitat Politècnica de València
2015-2024
Universidad de La Laguna
2014
Universitat de València
2014
University College London
2014
Academy of Sciences of Moldova
2014
Bhabha Atomic Research Centre
2012
University of Nevada, Las Vegas
2012
Heritage Malta
2012
Laboratoire de Chimie Moléculaire et Thioorganique
2011
Escola Politècnica Superior d'Alcoi
2004-2008
The structural and vibrational properties of bismuth selenide (Bi${}_{2}$Se${}_{3}$) have been studied by means x-ray diffraction Raman scattering measurements up to 20 30 GPa, respectively. complemented with ab initio total-energy lattice dynamics calculations. Our experimental results evidence a phase transition from the low-pressure rhombohedral ($R$-3$m$) (\ensuremath{\alpha}-Bi${}_{2}$Se${}_{3}$) sixfold coordination for Bi monoclinic $C$2/$m$ structure...
We report an experimental and theoretical lattice dynamics study of antimony telluride (Sb${}_{2}$Te${}_{3}$) up to 26 GPa together with a its structural stability under pressure. Raman-active modes the low-pressure rhombohedral (R-3m) phase were observed 7.7 GPa. Changes frequencies linewidths around 3.5 where electronic topological transition was previously found. Raman-mode changes evidence transitions at 7.7, 14.5, 25 The pressure coefficients new phases above 14.5 agree those calculated...
We report an experimental and theoretical lattice dynamics study of bismuth telluride (Bi${}_{2}$Te${}_{3}$) up to 23 GPa together with the optical absorption reflection 10 GPa. The indirect bandgap low-pressure rhombohedral (R-3$m$) phase (\ensuremath{\alpha}-Bi${}_{2}$Te${}_{3}$) was observed decrease pressure at a rate \ensuremath{-}6 meV/GPa. In regard dynamics, Raman-active modes \ensuremath{\alpha}-Bi${}_{2}$Te${}_{3}$ were 7.4 dependence their frequency width provides evidence...
We have studied by means of high-pressure x-ray diffraction the structural stability ${\text{Ni}}_{2}{\text{Mo}}_{3}\text{N}$, ${\text{Co}}_{3}{\text{Mo}}_{3}\text{N}$, and ${\text{Fe}}_{3}{\text{Mo}}_{3}\text{N}$. also report ab initio computing modeling properties these compounds, ${\text{Pd}}_{2}{\text{Mo}}_{3}\text{N}$ ${\text{Pt}}_{2}{\text{Mo}}_{3}\text{N}$. found that nitrides remain stable in ambient-pressure cubic structure at least up to 50 GPa determined their equation state. All...
Raman scattering measurements and lattice-dynamics calculations were performed on magnesium tungstate (MgWO${}_{4}$) under high pressure up to 41 GPa. Experiments carried out a selection of media. The influence nonhydrostaticity the structural properties MgWO${}_{4}$ isomorphic compounds is examined. Under quasihydrostatic conditions, phase transition was found at 26 GPa in MgWO${}_{4}$. high-pressure tentatively assigned triclinic structure similar that CuWO${}_{4}$. We also report discuss...
Abstract Bi 2 Se 3 , Te and Sb are narrow bandgap semiconductors with tetradymite crystal structure (R‐3m) which have been extensively studied along their alloys due to promising operation as thermoelectric materials in the temperature range between 300 500 K. Studies on these layered increased tremendously last years since they recently predicted demonstrated behave 3D topological insulators. In particular, a number of high‐pressure studies done recent materials. this work we summarize main...
Antimony trisulfide (Sb2S3), found in nature as the mineral stibnite, has been studied under compression at room temperature from a joint experimental and theoretical perspective. X-ray diffraction Raman scattering measurements are complemented with ab initio total-energy, lattice-dynamics, electronic structure calculations. The continuous changes observed volume, lattice parameters, axial ratios, bond lengths, mode frequencies function of pressure can be attributed to different...
We have studied BaWO${}_{4}$ under compression at room temperature by means of x-ray diffraction and Raman spectroscopy. When compressed with neon as a pressure-transmitting medium (quasihydrostatic conditions), we found that transforms from its low-pressure tetragonal structure into much denser monoclinic structure. This result confirms our previous theoretical prediction based on ab initio calculations the scheelite to BaWO${}_{4}$-II transition occurs if kinetic barriers are suppressed...
The high-pressure crystal structure, lattice-vibrations, and electronic band structure of BiSbO4 were studied by ab initio simulations. We also performed Raman spectroscopy, infrared diffuse-reflectance measurements, as well synchrotron powder X-ray diffraction. High-pressure diffraction measurements show that the remains stable up to at least 70 GPa, unlike other known MTO4-type ternary oxides. These experiments give information on pressure dependence unit-cell parameters. Calculations...
In this paper, we report the angle-dispersive x-ray diffraction data of barite, BaSO${}_{4}$, measured in a diamond-anvil cell up to pressure 48 GPa, using three different fluid pressure-transmitting media (methanol-ethanol mixture, silicone oil, and He). Our results show that BaSO${}_{4}$ exhibits phase transition at pressures range from 15 27 depending on used. This indicates nonhydrostatic stresses have crucial role high-pressure behavior compound. The new (HP) has been solved refined...
We report a joint experimental and theoretical study of the structural vibrational properties synthetic sphaerobismoite (β-Bi2O3) at high pressures in which room-temperature angle-dispersive X-ray diffraction (XRD) Raman scattering measurements have been complemented with ab initio total-energy lattice dynamics calculations. Striking changes spectra were observed around 2 GPa, whereas evidence no change tetragonal symmetry compound up to 20 GPa; however, significant exists compressibility...
A new wolframite-type polymorph of InVO4 is identified under compression near 7 GPa by in situ high-pressure (HP) X-ray diffraction (XRD) and Raman spectroscopic investigations on the stable orthorhombic InVO4. The structural transition accompanied a large volume collapse (ΔV/V = −14%) drastic increase bulk modulus (from 69 to 168 GPa). Both techniques also show existence third phase coexisting with low- phases limited pressure range close pressure. XRD studies revealed highly anisotropic In...
An experimental and theoretical study of the structural properties monoclinic bismuth oxide (alfa-Bi2O3) under high pressures is here reported. Both synthetic mineral bismite powder samples have been compressed up to 45 GPa their equations state determined with angle-dispersive x-ray diffraction measurements. Experimental results also compared calculations which suggest possibility several phase transitions below 10 GPa. However, experiments reveal only a pressure-induced amorphisation...
We have studied the structural behavior of bismuth phosphate under compression. performed x-ray powder diffraction measurements up to 31.5 GPa and ab initio calculations. Experiments were carried out on different polymorphs; trigonal (phase I) monoclinic (phases II III). Phases I III, at low pressure (0.2-0.8 GPa), transform into phase II, which has a monazite-type structure. At room temperature, this polymorph is stable GPa. Calculations support these findings predict occurrence an...
The effect of pressure on the vibrational properties bulk and nanocrystalline powders cubic bixbyite-type In2O3 has been investigated at room temperature by means Raman spectroscopy up to 31.6 30 GPa, respectively. We have able follow dependence sixteen seven modes in In2O3, experimental frequencies coefficients Raman-active ambient are good agreement with those predicted our theoretical ab initio calculations. Furthermore, a comparison data calculations for rhombohedral corundum...
The first pressure-induced solid-phase synthesis of a zeolite has been found through compression common zeolite, ITQ-29 (see scheme, Si yellow, O red). new microporous structure, ITQ-50, unique structure and improved performance for propene/propane separation with respect the parent material ITQ-29. As service to our authors readers, this journal provides supporting information supplied by authors. Such materials are peer reviewed may be re-organized online delivery, but not copy-edited or...
We report a joint experimental and theoretical study of the structural, vibrational, elastic, optical, electronic properties layered high-mobility semiconductor Bi2O2Se at high pressure. A good agreement between experiments ab initio calculations is observed for equation state, pressure coefficients Raman-active modes bandgap material. In particular, detailed description vibrational provided. Unlike other Sillén-type compounds which undergo tetragonal to collapsed pressure-induced phase...
Zircon-type holmium phosphate (HoPO4) and thulium (TmPO4) have been studied by single-crystal x-ray diffraction ab initio calculations. We report on the influence of pressure crystal structure, elastic thermodynamic properties. The equation state for both compounds is accurately determined. also obtained information polyhedral compressibility which used to explain anisotropic axial bulk compressibility. Both are ductile more resistive volume compression than shear deformation at all...
High pressure X-ray diffraction, Raman scattering, and electrical measurements, together with theoretical calculations, which include the analysis of topological electron density electronic localization function, evidence presence an isostructural phase transition around 2 GPa, a Fermi resonance 3.5 pressure-induced decomposition SnSb2Te4 into high-pressure phases its parent binary compounds (α-Sb2Te3 SnTe) above 7 GPa. The internal polyhedral compressibility, behavior Raman-active modes,...
Angle-dispersive X-ray diffraction measurements have been performed in acanthite, Ag2S, up to 18 GPa order investigate its high-pressure structural behavior. They complemented by ab initio electronic structure calculations. From our experimental data, we determined that two different phase transitions take place at 5 and 10.5 GPa. The first pressure-induced transition is from the initial anti-PbCl2-like monoclinic (space group P21/n) an orthorhombic Ag2Se-type P212121). compressibility of...
We report a joint experimental and theoretical investigation of the high pressure structural vibrational properties terbium sesquioxide (Tb2O3). Powder X-ray diffraction Raman scattering measurements show that cubic Ia3̅ (C-type) Tb2O3 undergoes two phase transitions up to 25 GPa. observe first irreversible reconstructive transition monoclinic C2/m (B-type) at ∼7 GPa subsequent reversible displacive from trigonal P3̅m1 (A-type) ∼12 Thus, is found follow well-known C → B A sequence in other...
In this paper we present the results of new experiments on ion irradiation water ice performed thin films to study synthesis hydrogen peroxide molecule and discuss possibility detecting it in icy mantles interstellar grains. The used experimental technique has been situ infrared spectroscopy. We have irradiated (i.e. thickness was smaller than penetration depth ion) with three different ions, namely 200 keV H+ He+ 400 Ar++. were carried out at temperatures 16 77 K. found that is produced by...
We have performed a theoretical and experimental study of the structural stability terbium phosphate at high pressures. Theoretical ab initio total-energy lattice-dynamics calculations together with x-ray diffraction experiments allowed us to completely characterize phase transition $\ensuremath{\sim}9.8\text{ }\text{GPa}$ from zircon monazite structure. Furthermore, been check relative 17 candidate structures different pressures allow propose...
High-pressure optical absorption and Raman scattering measurements have been performed in defect chalcopyrite (DC) CdGa2Se4 up to 22 GPa during two pressure cycles investigate the pressure-induced order-disorder phase transitions taking place this ordered-vacancy compound. Our reveal that on decreasing from GPa, sample does not revert initial but likely a disordered zinc blende (DZ) structure direct bandgap Raman-active modes of which measured second upstroke. complemented with electronic...