The system MgO-Al2O3-SiO2 under pressure: A computational study of melting relations and phase diagrams

Belmonte, Donato; Ottonello, G.; Zuccolini, Marino Vetuschi; Attene, Marco

doi:10.1016/j.chemgeo.2016.11.011

Cited by 30 publications

(39 citation statements)

References 85 publications

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“…The detail of presence and effect of oxygen in the film has been discussed in the previous article . In addition, the Gibbs free energy of Si 3 N 4 and SiO 2 is roughly −936 and −922 kJ mole −1 , respectively, indicating that the thermal stability of the two is very close . TaN has a Gibbs free energy of −604.96 kJ mole −1 , which is significantly higher than that of Ta 2 O 5 (−764.4 kJ mole −1 ).…”

Section: Resultsmentioning

confidence: 93%

Influence of Nitrogen Adsorption of Doped Ta on Characteristics of SiN_x‐Based Resistive Random Access Memory

Guo

Gao

Jiang

et al. 2019

Physica Status Solidi (a)

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The characteristics and conductive mechanism of Ta/SiN x /Ta:SiN x /SiN x /Pt resistive random access memory (RRAM) are investigated. Compared with Pt-doped devices with the same structure, the Ta-doped devices produce lower operation current in a high resistance state and a larger on/off radio. Furthermore, reliability tests show that the Ta-doped RRAM has good data retention ability and endurance. Ta clusters are observed in the Ta-doped SiN x layer through the transmission electron microscope. Also, the X-ray photoelectron spectra indicate that additional Si dangling bonds and tantalum nitride are present in the Ta-doped SiN x film. Based on the structure of the device, material analysis, and electrical characteristics, a model is proposed to explain the influence of the doped Ta on resistive switching behavior of the device.

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Section: Resultsmentioning

confidence: 93%

Influence of Nitrogen Adsorption of Doped Ta on Characteristics of SiN_x‐Based Resistive Random Access Memory

Guo

Gao

Jiang

et al. 2019

Physica Status Solidi (a)

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“…The addition of the equivalent amount of oxygen in the form of different types of volatiles (e.g., 4CO and 4H 2 O molecules) has nearly the same effect on the coordination number of oxygen by silicon. The addition of volatiles to a silicate melt results in a depolymerization reaction involving

{SiO}_{4}^{4 -}

monomers and three forms of oxygen: singly bonded non‐bridging O − (NBO), doubly bonded bridging O 0 (BO) and free oxygen O 2− (Belmonte et al., 2017; Ottonello et al., 2001; Ottonello & Moretti, 2004). The interaction of the added volatile with the silicate melt can be described by the dissociation of the volatile (e.g., CO 2 ⇔ C 4+ + 2O 2− ) followed by an anionic interaction (i.e., O 0 + O 2− ⇔ 2O − ; Toop & Samis, 1962).…”

Section: Resultsmentioning

confidence: 99%

“…SiO monomers and three forms of oxygen: singly bonded non-bridging O − (NBO), doubly bonded bridging O 0 (BO) and free oxygen O 2− (Belmonte et al, 2017;Ottonello et al, 2001;Ottonello & Moretti, 2004). The interaction of the added volatile with the silicate melt can be described by the dissociation of the volatile (e.g., CO 2 ⇔ C 4+ + 2O 2− ) followed by an anionic interaction (i.e., O 0 + O 2− ⇔ 2O − ; Toop & Samis, 1962).…”

Section: Structure Of the Meltsmentioning

confidence: 99%

Buoyancy and Structure of Volatile‐Rich Silicate Melts

Solomatova

Caracas

2021

JGR Solid Earth

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The early Earth was marked by at least one global magma ocean. Melt buoyancy played a major role for its evolution. Here we model the composition of the magma ocean using a six-component pyrolite melt, to which we add volatiles in the form of carbon as molecular CO or CO 2 and hydrogen as molecular H 2 O or through substitution for magnesium. We compute the density relations from firstprinciples molecular dynamics simulations. We find that the addition of volatiles renders all the melts more buoyant compared to the reference volatile-free pyrolite. The effect is pressure dependent, largest at the surface, decreasing to about 20 GPa, and remaining roughly constant to 135 GPa. The increased buoyancy would have enhanced convection and turbulence, and thus promoted the chemical exchanges of the magma ocean with the early atmosphere. We determine the partial molar volume of both H 2 O and CO 2 throughout the magma ocean conditions. We find a pronounced dependence with temperature at low pressures, whereas at megabar pressures the partial molar volumes are independent of temperature. At all pressures, the polymerization of the silicate melt is strongly affected by the amount of oxygen added to the system while being only weakly affected by the specific type of volatile added.

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“…Most of the attempts made so far in the literature [1][2][3][4][5][6][7][8] rely on phase equilibrium models, which are based on the assessment of experimental datasets, while very few of them use first principles data to calculate phase diagrams [9][10][11][12]. However, a full ab initio thermodynamic database for phase equilibria calculation at high pressure and temperature (HP-HT) has not been created yet, even for simple compositional systems.…”

Section: Introductionmentioning

confidence: 99%

First Principles Thermodynamics of Minerals at HP–HT Conditions: MgO as a Prototypical Material

Belmonte

2017

Minerals

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Ab initio thermodynamic properties, equation of state and phase stability of periclase (MgO, B1-type structure) have been investigated in a broad P-T range (0-160 GPa; 0-3000 K) in order to set a model reference system for phase equilibria simulations under deep Earth conditions. Phonon dispersion calculations performed on large supercells using the finite displacement method and in the framework of quasi-harmonic approximation highlight the performance of the Becke three-parameter Lee-Yang-Parr (B3LYP) hybrid density functional in predicting accurate thermodynamic functions (heat capacity, entropy, thermal expansivity, isothermal bulk modulus) and phase reaction boundaries at high pressure and temperature. A first principles Mie-Grüneisen equation of state based on lattice vibrations directly provides a physically-consistent description of thermal pressure and P-V-T relations without any need to rely on empirical parameters or other phenomenological formalisms that could give spurious anomalies or uncontrolled extrapolations at HP-HT. The post-spinel phase transformation, Mg 2 SiO 4 (ringwoodite) = MgO (periclase) + MgSiO 3 (bridgmanite), is taken as a computational example to illustrate how first principles theory combined with the use of hybrid functionals is able to provide sound results on the Clapeyron slope, density change and P-T location of equilibrium mineral reactions relevant to mantle dynamics.

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The system MgO-Al2O3-SiO2 under pressure: A computational study of melting relations and phase diagrams

Cited by 30 publications

References 85 publications

Influence of Nitrogen Adsorption of Doped Ta on Characteristics of SiN_x‐Based Resistive Random Access Memory

Influence of Nitrogen Adsorption of Doped Ta on Characteristics of SiN_x‐Based Resistive Random Access Memory

Buoyancy and Structure of Volatile‐Rich Silicate Melts

First Principles Thermodynamics of Minerals at HP–HT Conditions: MgO as a Prototypical Material

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The system MgO-Al2O3-SiO2 under pressure: A computational study of melting relations and phase diagrams

Cited by 30 publications

References 85 publications

Influence of Nitrogen Adsorption of Doped Ta on Characteristics of SiNx‐Based Resistive Random Access Memory

Influence of Nitrogen Adsorption of Doped Ta on Characteristics of SiNx‐Based Resistive Random Access Memory

Buoyancy and Structure of Volatile‐Rich Silicate Melts

First Principles Thermodynamics of Minerals at HP–HT Conditions: MgO as a Prototypical Material

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Product

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Influence of Nitrogen Adsorption of Doped Ta on Characteristics of SiN_x‐Based Resistive Random Access Memory

Influence of Nitrogen Adsorption of Doped Ta on Characteristics of SiN_x‐Based Resistive Random Access Memory