Structure of liquids and glasses in the Ge–Se binary system

Salmon, Philip S.

doi:10.1016/j.jnoncrysol.2007.05.152

Cited by 104 publications

(158 citation statements)

References 109 publications

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“…The close similarity between the b Ge and b Se values for Ge and Se of natural isotopic abundance means that S(q) ≃ S NN (q) to an excellent level of approximation (Salmon, 2007a), where S NN (q) is given by equation (1) if b Ge = b Se . The total pair-distribution function g(r) follows from the Fourier transform relation…”

Section: Theorymentioning

confidence: 87%

“…The experiments used samples containing Ge and Se of natural isotopic abundance, for which the coherent neutron scattering lengths take similar values, i.e., b Ge = 8.185(20) fm and b Se = 7.970(9) fm (Sears, 1992). In consequence, the Bhatia and Thornton (1970) number-number partial structure factor S NN (q) is measured to an excellent level of approximation, where q denotes the magnitude of the scattering vector (Salmon, 2007a). This function and its Fourier transform, the number-number partial pair-distribution function g NN (r), do not distinguish between the chemical species that occupy the atomic sites in a glass-forming network structure, and therefore yield important information on the topological ordering (Salmon, 1992;Salmon and Liu, 1994;Petri et al, 1999).…”

Section: Introductionmentioning

confidence: 99%

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Topological Ordering and Viscosity in the Glass-Forming Ge–Se System: The Search for a Structural or Dynamical Signature of the Intermediate Phase

et al. 2017

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The topological ordering of the network structure in vitreous Ge x Se 1−x was investigated across most of the glass-forming region (0 ≤ x ≤ 0.4) by using high-resolution neutron diffraction to measure the Bhatia-Thornton number-number partial structure factor. This approach gives access to the composition dependence of the mean coordination number n and correlation lengths associated with the network ordering. The thermal properties of the samples were also measured by using temperature-modulated differential scanning calorimetry. The results do not point to a structural origin of the so-called intermediate phase, which in our work is indicated for the composition range 0.175(8) ≤ x ≤ 0.235(8) by a vanishingly small non-reversing enthalpy near the glass transition. The midpoint of this range coincides with the mean-field expectation of a floppy-to-rigid transition at x = 0.20. The composition dependence of the liquid viscosity, as taken from the literature, was also investigated to look for a dynamical origin of the intermediate phase, using the Mauro-YueEllison-Gupta-Allan (MYEGA) model to estimate the viscosity at the liquidus temperature. The evidence points to a maximum in the viscosity at the liquidus temperature, and a minimum in the fragility index, for the range 0.20 ≤ x ≤ 0.22. The utility of the intermediate phase as a predictor of the material properties in network glass-forming systems is discussed.

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Section: Theorymentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Topological Ordering and Viscosity in the Glass-Forming Ge–Se System: The Search for a Structural or Dynamical Signature of the Intermediate Phase

et al. 2017

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“…In both GeSe4In10 and GeSe4In15, the first coordination shell peak was at 2.4 Å and the peak extended up to 2.6 Å. It is usual for Se-Se and Ge-Se nearest neighbor distances to lie well within the first shell of interatomic interactions of complex Ge-Se-In systems, as determined by ND (Se-Se peak at 2.32 Å and Ge-Se peak at 2.36 Å, respectively) [25]. However, we noticed considerable variance in the partials that comprised the first coordination shell in respect to In content.…”

Section: Pair Distribution Functionsmentioning

confidence: 94%

The Effect of Indium Content on the Atomic Environment and Cluster Stability of GeSe4Inx=10,15 Glasses

Antipas

Mangiorou

Hristoforou

2015

Metals

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Abstract:The atomic environments of two chalcogenide glasses, with compositions GeSe4In10 and GeSe4In15, were studied via Reverse Monte Carlo and Density Functional Theory. Indium content demoted Ge-Se bonding in favor of Se-In while the contribution of Se-Se in the first coordination shell order was faint. Upon transition to the richer In glass, there was formation of rich Ge-centered clusters at radial distances further than 4 Å from the RMC box center, which was taken to signify a reduction of Ge-Se interactions. Cluster coordination by Se promoted stability while, very conclusively, In coordination lowered cluster stability by intervening in the Ge-Se and Se-Se networks.

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“…Therefore, a large number of experimental and theoretical works have been done for nearly half a century [4]. The preceding experiments on the molar volume [5] and sound velocity [6] suggest structural changes of a crossover type at high temperatures above 900 o C, however the maximum temperatures covered by these investigations were not high enough to definitely show the liquid-liquid crossover transition in liquid GeSe 2 .…”

Section: Introductionmentioning

confidence: 99%

“…Neutron diffraction experiments at three temperatures have shown that structure changes over 300 K temperature intervals [4]. However, it has not been clarified yet whether or not the thermodynamic functions of the Ge-Te system have characteristic of liquid-liquid transition as observed in the liquid Ge-Te system.…”

Section: Introductionmentioning

confidence: 99%

Novel liquid-liquid transition in the liquid Se-GeSe system

Tsuchiya

2011

EPJ Web of Conferences

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Abstract. The sound velocity in the liquid Se-SeGe system under the saturated vapor pressure was measured at every 1 degree. A minimum in the sound velocity as a function of temperature has been observed for alloys with 12.5 to 45 at.% Ge, which suggests that the crossover liquid-liquid transition occurs in the liquid around GeSe 2 . In addition to the minimum, it has been found for alloys with 15 to 27.5 at.% Ge that the sound velocity decreases rather stepwise. The reproducibility has been checked for different samples with the same composition and for different ultrasonic transducers. The decrease occurs in a very narrow temperature interval, a few degrees, and shows hysteresis depending on thermal treatments. The position of this temperature region lowers with increasing Ge concentration, and appears to merge into a minimum in the sound velocity around GeSe 2 . Novel structural changes, being the first order in nature, occur slightly below the crossover transition.

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Structure of liquids and glasses in the Ge–Se binary system

Cited by 104 publications

References 109 publications

Topological Ordering and Viscosity in the Glass-Forming Ge–Se System: The Search for a Structural or Dynamical Signature of the Intermediate Phase

Topological Ordering and Viscosity in the Glass-Forming Ge–Se System: The Search for a Structural or Dynamical Signature of the Intermediate Phase

The Effect of Indium Content on the Atomic Environment and Cluster Stability of GeSe4Inx=10,15 Glasses

Novel liquid-liquid transition in the liquid Se-GeSe system

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