0000000000124232

AUTHOR

Eduardo Machado-charry

showing 3 related works from this author

High-pressure electronic structure and phase transitions in monoclinic InSe: X-ray diffraction, Raman spectroscopy, and density functional theory

2008

We have studied the crystal and electronic structure of monoclinic (MC) InSe under pressure finding a reversible phase transition to a ${\mathrm{Hg}}_{2}{\mathrm{Cl}}_{2}$-like tetragonal phase. The pressure evolution of the crystal structure was investigated by angle-dispersive x-ray diffraction and Raman spectroscopy in a diamond-anvil cell up to $30\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. From the diffraction experiments, we deduced that MC InSe becomes gradually more symmetric under pressure, transforming the crystal structure into a tetragonal one at $19.4\ifmmode\pm\else\textpm\fi{}0.5\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. This phase transition occurs without any volume change. Ra…

Phase transitionMaterials sciencebusiness.industry02 engineering and technologyCrystal structure021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesPressure coefficientElectronic Optical and Magnetic MaterialsTetragonal crystal systemCrystallographysymbols.namesakeOptics[PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other]Phase (matter)0103 physical sciencesX-ray crystallographysymbols62.50.010306 general physics0210 nano-technologybusinessRaman spectroscopyMonoclinic crystal systemPhysical Review B
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GaS and InSe equations of state from single crystal diffraction

2007

We have performed single crystal angle dispersive X-ray diffraction at high pressure in order to investigate the GaS and InSe equations of state. We situate the transition from β-GaS to GaS-II at 2 7 0 3. ± . GPa. In the InSe experiment we locate the beginning of the phase transition at 7.6 ± 0.6 GPa. The equations of state of β-GaS ( 0 43 27 0 06V = . ± . Å 3 , 37 2 GPaB = ± , 5 2B = .¢ ), GaS-II ( 0 42 4 0 2V = . ± . Å 3 , 50 3 GPaB = ± and 4 3 0 3B = . ± .¢ ) and γ-InSe ( 0 58 4 0 2V = . ± . Å 3 , 24 3 GPaB = ± and 8 6 0 8B = . ± .¢ ) are discussed and compared with the results of an ab-initio calculation.

DiffractionPhase transitionChemistryScattering02 engineering and technology021001 nanoscience & nanotechnologyCondensed Matter Physics01 natural sciencesSingle Crystal DiffractionElectronic Optical and Magnetic MaterialsCrystallographyAb initio quantum chemistry methodsHigh pressure[PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other]0103 physical sciencesX-ray crystallographyPACS : 61.10.Nz 61.82.Fk 62.50.+p 64.30.+t010306 general physics0210 nano-technologySingle crystal
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First-principles study of the electronic structure of cubicGaS: Metallic versus insulating polymorphs

2007

The electronic structure of different polymorphs of gallium sulphide $(\mathrm{GaS})$ with cubic structure is investigated by means of first-principles band structure calculations in connection with experimental reports on a metastable semiconducting cubic form of this material. The expected metallic character of simple cubic phases containing one $\mathrm{GaS}$ group per unit cell (rocksalt or zinc-blende) is confirmed by the calculations. A cubane-based zinc-blende structure is found to exhibit a band gap which is compatible with experimental results but the unit cell parameter is much larger than the reported ones. We have also studied cubic phases containing hydrogen. It is found that t…

Materials scienceCondensed matter physicsBand gapElectronic structureCubic crystal systemCondensed Matter PhysicsElectronic Optical and Magnetic Materialschemistry.chemical_compoundchemistryCubanePhase (matter)MetastabilityCubic formElectronic band structurePhysical Review B
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