Transformation pathways of silica under high pressure

Huang, Liping; Durandurdu, Murat; Kieffer, John

doi:10.1038/nmat1760

Cited by 91 publications

(99 citation statements)

References 35 publications

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“…6) [272]. The discovery of this new phase opens the way to obtain new materials with P in octahedral coordination and supports the two-step densification mechanism observed in isoelectronic SiO 2 [273,274].…”

Section: Featuresupporting

confidence: 67%

Pressure‐induced structural phase transitions in materials and earth sciences

Manjón

Errandonea

2008

Physica Status Solidi (b)

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Pressure is an important thermodynamic parameter since it allows an increase of matter density by reducing volume. The reduction of volume by applying high pressures leads to an overall decrease of interatomic and intermolecular distances that allows exploring in detail atomic and molecular interactions. Therefore, high‐pressure research has improved our fundamental understanding of these interactions in solids, liquids and gasses. The study of the structure of matter under compression is a rapid developing field that is receiving increasing attention especially due to continuous experimental and theoretical developments. In this article, we give a brief description of the experimental and theoretical methods employed in the study of solid matter at high pressures and summarize the high‐pressure phases of the most relevant elements and inorganic compounds of the AX, A2X, AX2, ABX2, A2X3, ABX3, ABX4 and AB2X4 families giving an overview of the state of the art in high‐pressure research by highlighting recent discoveries, hot spots, controversial questions, and future directions of research. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Section: Featuresupporting

confidence: 67%

Pressure‐induced structural phase transitions in materials and earth sciences

Manjón

Errandonea

2008

Physica Status Solidi (b)

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“…To our best knowledge, this was the first time that I4 In order to compare the relative stability of α-, β'-and ideal β-cristobalite, we carried out DFT total energy calculations at different cell volumes without symmetry constraints, following similar procedures in an early work 33 . Figure 2 shows that α-cristobalite is stable below 45 energy difference (~0.01 eV/SiO 2 ) between α-and β'-cristobalite was found in our DFT calculations, in good agreement with other first principles calculations 10,16,32 .…”

Section: Resultsmentioning

confidence: 99%

α–βtransformation and disorder inβ-cristobalite silica

Yuan

Huang

2012

Phys. Rev. B

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Disorder in β-cristobalite is shown to arise from the conformational changes between alphaand beta-rings (energy barriers of 10-30 meV/SiO 2 ). Alpha-rings, remnants from the α-β transformation, constitute α-cristobalite. Beta-rings are local structures of a new β'-cristobalite of symmetry I4 __ 2d, confirmed herein by both molecular dynamics simulations and first-principles calculations. The ring conformation in β-cristobalite features a short correlation time (<50 fs) and short correlation length (<1 nm), giving the underlying topology framework the ability to support the dynamic disorder.

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“…As an example, it is known that the amorphization transition in α-SiO 2 is highly sensitive to the degree of nonhydrostaticity produced by the pressuretransmitting medium [67][68][69][70]. Therefore, it is advisable to perform experiments using powder and single crystals and with different pressure-transmitting media in order to fully understand the PIA process in a given material.…”

Section: Mechanical and Dynamical Stabilitymentioning

confidence: 99%

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

et al. 2016

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We report a joint experimental and theoretical study of the optical properties of tetragonal bismuth oxide (β-Bi 2 O 3 ) at high pressure by means of optical absorption measurements combined with ab initio electronic band structure calculations. Our results are consistent with previous results that show the presence of a second-order isostructural phase transition in Bi 2 O 3 (from β to β ) around 2 GPa and a phase transition above 15 GPa combined with a pressure-induced amorphization above 17-20 GPa. In order to further understand the pressure-induced phase transitions and amorphization occurring in β-Bi 2 O 3 , we theoretically studied the mechanical and dynamical stability of the tetragonal structures of β-and β -Bi 2 O 3 at high pressure through calculations of their elastic constants, elastic stiffness coefficients, and phonon dispersion curves. The pressure dependence of the elastic stiffness coefficients and phonon dispersion curves confirms that the isostructural phase transition near 2 GPa is of ferroelastic nature. Furthermore, a topological study of the electron density shows that the ferroelastic transition is not caused by a change in number of critical points (cusp catastrophe), but by the equalization of the electron densities of both independent O atoms in the unit cell due to a local rise in symmetry. Finally, from theoretical simulations, β -Bi 2 O 3 is found to be mechanically and dynamically stable at least up to 26.7 GPa under hydrostatic conditions; thus, the pressure-induced amorphization reported above 17-20 GPa in powder β -Bi 2 O 3 using methanol-ethanol-water as pressure-transmitting medium could be related to the frustration of a reconstructive phase transition at room temperature and the presence of mechanical or dynamical instabilities under nonhydrostatic conditions.

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Transformation pathways of silica under high pressure

Cited by 91 publications

References 35 publications

Pressure‐induced structural phase transitions in materials and earth sciences

Pressure‐induced structural phase transitions in materials and earth sciences

α–βtransformation and disorder inβ-cristobalite silica

β−Bi2O3under compression: Optical and elastic properties and electron density topology analysis

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