Simulation of pressure-induced polyamorphism in a chalcogenide glass<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">GeSe</mml:mi></mml:mrow><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>

Durandurdu, Murat; Drabold, D. A.

doi:10.1103/physrevb.65.104208

Cited by 80 publications

(70 citation statements)

References 37 publications

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“…Similarly Se-Se bonds are decreased to 6% from 8% bonds in the bulk model. This seems consistent with the pressure induced effect on this system as studied by Durandurdu et al [7]. The reason could be that quenching the system in the slab geometry is thermodynamically similar to the quenching under constant pressure.…”

Section: Coordination and Ring Statisticssupporting

confidence: 80%

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Theoretical study of an amorphous chalcogenide surface

Inam

Drabold

2008

Journal of Non-Crystalline Solids

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Section: Coordination and Ring Statisticssupporting

confidence: 80%

“…Concentration of wrong bonds in these models is found to vary when such models are relaxed under different pressures [7]. Ge-Ge bonds are found to be relatively unstable under pressure as compared to Se-Se bonds.…”

Section: Introductionmentioning

confidence: 97%

Theoretical study of an amorphous chalcogenide surface

Inam

Drabold

2008

Journal of Non-Crystalline Solids

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“…For example, the pressure-dependent properties of the stressed-rigid glass GeSe 2 have been probed by x-ray and neutron diffraction [33][34][35][36], x-ray absorption spectroscopy [36], Raman spectroscopy [37,38], sound velocity [39], electrical conductivity [40,41], and first-principles molecular dynamics (FPMD) [34,42] methods. It is unclear, however, as to whether there is an abrupt semiconductor-glass to metal-crystal transition [40,41], or a gradual evolution in the structure to give a more metallic glass [33][34][35][36]42], the details of which may be sensitive to the thermal history [34]. At pressures below ∼8.5 GPa, neutron diffraction and FPMD results reveal a self-consistent picture in which there is no change ton but a trade-off between the fractions of corner-and edge-sharing tetrahedra with increasing density.…”

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confidence: 99%

Pressure-induced structural changes in the network-forming isostatic glassGeSe4: An investigation by neutron diffraction and first-principles molecular dynamics

et al. 2016

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The changes to the topological and chemical ordering in the network-forming isostatic glass GeSe 4 are investigated at pressures up to ∼14.4 GPa by using a combination of neutron diffraction and first-principles molecular dynamics. The results show a network built from corner-and edge-sharing Ge(Se 1/2 ) 4 tetrahedra, where linkages by Se 2 dimers or longer Se n chains are prevalent. These linkages confer the network with a local flexibility that helps to retain the network connectivity at pressures up to ∼8 GPa, corresponding to a density increase of ∼37%. The network reorganization at constant topology maintains a mean coordination number n 2.4, the value expected from mean-field constraint-counting theory for a rigid stress-free network. Isostatic networks may therefore remain optimally constrained to avoid stress and retain their favorable glass-forming ability over a large density range. As the pressure is increased to around 13 GPa, corresponding to a density increase of ∼49%, Ge(Se 1/2 ) 4 tetrahedra remain as the predominant structural motifs, but there is an appearance of 5-fold coordinated Ge atoms and homopolar Ge-Ge bonds that accompany an increase in the fraction of 3-fold coordinated Se atoms. The band gap energy decreases with increasing pressure, and midgap states appear at pressures beyond ∼6.7 GPa. The latter originate from undercoordinated Se atoms that terminate broken Se n chains.

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“…Polyamorphism was first observed in compressed ice 8 and since then has been experimentally and theoretically studied in a number of other common elements and compounds like Si 2,9 , Ge 10 , SiO 2 11,12 , etc. While in some cases the amorphous-amorphous transition (AAT) was found to be sharp [8][9][10] , in other systems it was observed to proceed gradually 11,13 . The sharpness of the transition might also be temperature dependent, as observed, e.g.…”

Section: Introductionmentioning

confidence: 99%

Study of pressure-induced amorphization in sulfur usingab initiomolecular dynamics

Plašienka

Martoňák

2012

Phys. Rev. B

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We report results of ab initio constant-pressure molecular dynamics simulations of sulfur compression leading to structural transition and pressure-induced amorphization. Starting from the orthorhombic S-I phase composed of S8 ring molecules we find at room temperature and pressure of 20 GPa a transformation to monoclinic phase where half of the molecules develop a different conformation. Upon further compression, the monoclinic phase undergoes pressure-induced amorphization into an amorphous phase, in agreement with experiments. We study the dynamics of the amorphization transition and investigate the evolution of intra and intermolecular distances in the monoclinic phase in order to provide a microscopic insight into the rings disintegration process leading to amorphization. In the amorphous form we examine the structural properties and discuss its relation to the experimentally found amorphous form and to underlying crystal phases as well. The amorphous form we find appears to correspond to the experimentally observed low density amorphous form.

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Simulation of pressure-induced polyamorphism in a chalcogenide glassGeSe2

Cited by 80 publications

References 37 publications

Theoretical study of an amorphous chalcogenide surface

Theoretical study of an amorphous chalcogenide surface

Pressure-induced structural changes in the network-forming isostatic glassGeSe4: An investigation by neutron diffraction and first-principles molecular dynamics

Study of pressure-induced amorphization in sulfur usingab initiomolecular dynamics

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