First sharp diffraction peak in silicate glasses: Structure and scattering length dependence

Du, Jincheng; Corrales, L. René

doi:10.1103/physrevb.72.092201

Cited by 89 publications

(94 citation statements)

References 23 publications

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“…Although Si atoms remain four-fold coordinated with oxygen atoms in all glasses, the CN of Na and K atoms shows a variation with composition. As expected, the average CN of Na and K is around 6 and 8 for the binary Na and K glasses, respectively [33]. However, as shown in Fig.…”

mentioning

confidence: 83%

Thermometer Effect: Origin of the Mixed Alkali Effect in Glass Relaxation

Wang

Smedskjær

et al. 2017

Phys. Rev. Lett.

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mentioning

confidence: 83%

Thermometer Effect: Origin of the Mixed Alkali Effect in Glass Relaxation

Wang

Smedskjær

et al. 2017

Phys. Rev. Lett.

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“…This method has been successfully applied to a number of alkali silicate, rare-earth aluminate, and silicate simulations. 19,[22][23][24][25][26][27] The partial atomic charges and Buckingham potential parameters are shown in Table I.…”

Section: Molecular-dynamics Simulationsmentioning

confidence: 99%

Temperature-dependent structural heterogeneity in calcium silicate liquids

et al. 2010

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X-ray diffraction measurements performed on aerodynamically levitated CaSiO 3 droplets have been interpreted using a structurally heterogeneous liquid-state model. When cooled, the high-temperature liquid shows evidence of the polymerization of edge shared Ca octahedra. Diffraction isosbestic points are used to characterize the polymerization process in the pair-distribution function. This behavior is linear in the hightemperature melt but exhibits rapid growth just above the glass transition temperature around 1.2T g . The heterogeneous liquid interpretation is supported by molecular-dynamics simulations which show the CaSiO 3 glass has more edge-shared polyhedra and fewer corner shared polyhedra than the liquid model.

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“…A relationship between pre-existing defects in RPD nc-SiO 2 and MRO results in discrete dihedral angles extending to 3rd and generally 4th nearest-neighbors [9]. This scale of MRO is established by position of the FSDP in the structure factor from X-ray or neutron diffraction [2,3]. Analysis of the FSDP yields a λcorr in SiO 2 of ~0.4 to 0.5 nm corresponding to discrete dihedral angles bridging Si-O-Si bonds, and a larger coherence length, λcoh identifies nonperiodically organized clusters with dimensions ~1 nm.…”

Section: Methodsmentioning

confidence: 99%

“…It is equally important to distinguish the spin-orbit splitting, ΔSO of the centrosymmetric core states from the final state values of ΔSO' in O K edge spectra. Additionally, and of particular importance for nc-SiO 2 , GeO 2 , and Ge(S,SE) 2 , a non-zero value of ΔLF requires a scale of coherent-order extending up to, and generally beyond, 3rd…”

Section: Introductionmentioning

confidence: 99%

Process induced pre-existing defects in non-crystalline SiO₂and GeO₂at vacated O-atom bonding sites and comparisons with Ge-S(Se) alloy bonding sites

Lucovsky¹,

Zeller²,

Kim³

et al. 2013

J. Phys.: Conf. Ser.

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Three related topics are addressed in this article: (i) X-ray spectroscopy (XAS) studies of remote plasma deposited (RPD) nc-SiO 2 and nc-GeO 2 emphasizing (a) band-edge states and (b) pre-existing bonding defects; (ii) interpretation of X-ray absorption and photoemission spectra based on many electron theory, and in particluar charge transfer multiplets (CTs); and (iii) band-edge electronic structure and intrinsic defects in nc-SiO 2 and nc-GeO 2 thin films and their interfaces with Si and Ge substrates. The most significant result is the identification of local atomic structure in medium range order (MRO) clusters in which the pre-existing defects are embedded. These defects are vacated O-atom sites in which O-atoms have never been resident. They are confined to 1 nm scale chemically-ordered clusters distributed non-periodically with quartz-structured 4-fold coordinated Si(Ge) and 2-fold coordinated O bonding in 12-atom regular rings. Vacated O-atom sites defects are formed during processing and annealing, and reducing macroscopic as well as local bond-strain strain. They are qualitatively different, and readily distinguished from defects introduced by electrical, and by X-ray, γ-ray or high energy electron stressing of nc-SiO 2 and nc-GeO 2 . IntroductionIt is significant to note that ESR-active pre-existing defects detected in nc-SiO 2 and nc-GeO 2 , and in Se-rich Ge 1-x Se x alloys are qualitatively different. This is due quantitative differences in medium range order (MRO) between oxides and chalcogenides. MRO is order is by definition order beyond the regimes of (i) bond-lengths or 2-atom atom distances, and (iii) 3-atom correlated bond-angles. S-atoms and Se-atoms form S-S and Se-Se bonds, where O-atoms do not except in peroxides which have not been detected in irradiated SiO 2 bulk glasses or films. MRO is correlated with d-state ligand field splittings, ΔLF. These are non-zero when molecular orbital theory descriptions of valence band states in which case the number of valence band features is either 3 or more in compound and alloy oxides and chalcogenides [1]. The ΔLF are energy differences in 5-fold degenerate atomic core level d-states induced by non-spherical local symmetry in the valence band structure, or in virtual bound states in the conduction band regime as well. Of particular importance are the values of ΔLF associated with O-vacancy defect sites. These are split into 2-fold degenerate eg states and 3-fold degenerate t2g spectral regimes. This splitting is a direct consequence the non-spherical local symmetry and the medium range order (MRO) at the vacated O-atom sites [1]. Values of ΔLF, in electron volts (eV), are obtained by X-ray absorption (XAS) and electron energy loss spectroscopy (EELS). The same values can also be extracted from dielectric constants obtained from a dispersion analysis of (i) reflectivity (R), and (ii) spectroscopic ellipsometry (SE) spectral data. ΔLF is local symmetry, atomic coordination, and atom specific. It is equally important to distinguish the spi...

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First sharp diffraction peak in silicate glasses: Structure and scattering length dependence

Cited by 89 publications

References 23 publications

Thermometer Effect: Origin of the Mixed Alkali Effect in Glass Relaxation

Thermometer Effect: Origin of the Mixed Alkali Effect in Glass Relaxation

Temperature-dependent structural heterogeneity in calcium silicate liquids

Process induced pre-existing defects in non-crystalline SiO₂and GeO₂at vacated O-atom bonding sites and comparisons with Ge-S(Se) alloy bonding sites

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First sharp diffraction peak in silicate glasses: Structure and scattering length dependence

Cited by 89 publications

References 23 publications

Thermometer Effect: Origin of the Mixed Alkali Effect in Glass Relaxation

Thermometer Effect: Origin of the Mixed Alkali Effect in Glass Relaxation

Temperature-dependent structural heterogeneity in calcium silicate liquids

Process induced pre-existing defects in non-crystalline SiO2and GeO2at vacated O-atom bonding sites and comparisons with Ge-S(Se) alloy bonding sites

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Product

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Process induced pre-existing defects in non-crystalline SiO₂and GeO₂at vacated O-atom bonding sites and comparisons with Ge-S(Se) alloy bonding sites