Oscillating behavior of high-pressure stability observed in the immiscible Co–Cu system by first-principles calculation

2007 ◽  
Vol 101 (5) ◽  
pp. 056102 ◽  
Author(s):  
Yi Kong ◽  
Jiahao Li ◽  
Baixin Liu
Keyword(s):  
High Pressure ◽  
First Principles ◽  
First Principles Calculation ◽  
Pressure Stability

scholarly journals First Principles Calculation of the Stability of Iron Bearing Carbonates at High Pressure Conditions

Minerals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 54
Author(s):  
Jun Tsuchiya ◽  
Risa Nishida ◽  
Taku Tsuchiya
Keyword(s):  
High Pressure ◽  
High Spin ◽  
First Principles ◽  
Lower Mantle ◽  
Local Density ◽  
First Principles Calculation ◽  
Generalized Gradient ◽  
Carbonate Minerals ◽  
Pressure Stability ◽  
The Stability

Carbonate minerals such as ferromagnesite (Mg,Fe)CO 3 are suggested to be a possible major deep-carbon host in the lower mantle, because ferromagnesite is possibly stabilized by Fe spin crossover under pressure. However, the behavior of Fe-bearing carbonates under lower mantle pressure conditions has not been suitably examined thus far. Thus, in this study, we investigate the high-pressure stability of ferromagnesite and possible high-pressure structures with the chemical composition of (Mg 0.833 Fe 0.167 )CO 3 via first principles calculation using internally consistent local density approximation with Hubbard parameter (LDA+U) method, which can more accurately account for the electronic state of Fe than the LDA and generalized gradient approximation (GGA) approaches. The enthalpy values obtained via our calculations suggest that (Mg 0.833 Fe 0.167 )CO 3 undergoes phase transition from the R 3 ¯ c structure (high spin) to the P 1 ¯ (high spin) at 50 GPa, and to C2/m (high-spin) structure above 80 GPa, under static 0 K conditions. Therefore, no spin transitions in these carbonate minerals is expected under the lower mantle pressure conditions.

Pressure effects on mechanical and electronic properties of metallic C14 by first-principles calculation

2019 ◽  
Vol 33 (18) ◽  
pp. 1950193
Author(s):  
Yingjiao Zhou ◽  
Qun Wei ◽  
Bing Wei ◽  
Ruike Yang ◽  
Ke Cheng ◽  
...  
Keyword(s):  
High Pressure ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Pressure Range ◽  
Phonon Dispersion ◽  
Elastic Anisotropy ◽  
Acoustic Velocity ◽  
Pressure Effects ◽  
First Principles Calculation ◽  
First Principles Calculations

The elastic constants and phonon dispersion of metallic C[Formula: see text] are calculated by first-principles calculations. The results show that the metallic C[Formula: see text] is mechanically and dynamically stable under high pressure. The variations of G/B ratio, Poisson’s ratio, elastic anisotropy, acoustic velocity and Debye temperature at the pressure range from 0 GPa to 100 GPa are analyzed. The results reveal that by adjusting the pressures the elastic anisotropy and thermodynamic properties could be improved for better applicability.

Optical Properties of the High-Pressure Phases of SnO2: First-Principles Calculation

2010 ◽  
Vol 114 (2) ◽  
pp. 1052-1059 ◽  
Author(s):  
Yanlu Li ◽  
Weiliu Fan ◽  
Honggang Sun ◽  
Xiufeng Cheng ◽  
Pan Li ◽  
...  
Keyword(s):  
High Pressure ◽  
Optical Properties ◽  
First Principles ◽  
First Principles Calculation

First principles calculation of a high-pressure hydrous phase, δ-AlOOH

2002 ◽  
Vol 29 (19) ◽  
pp. 15-1-15-4 ◽  
Author(s):  
Jun Tsuchiya ◽  
Taku Tsuchiya ◽  
Shinji Tsuneyuki ◽  
Takamitsu Yamanaka
Keyword(s):  
High Pressure ◽  
First Principles ◽  
First Principles Calculation ◽  
Hydrous Phase

First-principles calculation of elastic and thermodynamic properties of MgO and SrO under high pressure

2006 ◽  
Vol 373 (2) ◽  
pp. 334-340 ◽  
Author(s):  
Yun-Dong Guo ◽  
Xin-Lu Cheng ◽  
Li-Ping Zhou ◽  
Zi-Jiang Liu ◽  
Xaing-Dong Yang
Keyword(s):  
High Pressure ◽  
Thermodynamic Properties ◽  
First Principles ◽  
First Principles Calculation

Novel elastic evolution of carbide Mo2Ga2C under pressure: Ab initio theoretical investigation

2019 ◽  
Vol 33 (30) ◽  
pp. 1950358
Author(s):  
Rui Wu ◽  
Hai-Chen Wang ◽  
Yan Yang ◽  
Li Ma ◽  
Shan Jiang ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Elastic Constants ◽  
Pressure Dependence ◽  
First Principles ◽  
Phonon Mode ◽  
First Principles Calculation ◽  
Max Phases ◽  
Transverse Acoustic ◽  
Phonon Structure

The pressure dependence of elastic properties of Mo2Ga2C is studied via first-principles calculation. The present investigation shows that differing from other MAX phases, in Mo2Ga2C the [Formula: see text] is larger than [Formula: see text], because of the strong Ga–Ga interlayer bonds along [Formula: see text]-axis. Moreover, under pressure, the [Formula: see text] increases more rapidly, originating from the faster strengthening of Ga–Ga bonds. Interestingly, elastic constants [Formula: see text] soften under high pressure (more than 20 GPa). Especially, the calculated phonon structure demonstrates that transverse acoustic (TA) phonon mode also softens under pressure, implying possible phase transition. The reduction of [Formula: see text] and softening of phonon mode are attributed to significantly weakened Mo–Mo interaction in contrast to the strengthening of Ga–Ga bonds under high pressure. Our present results further indicate that Mo2Ga2C is more ductile under pressure.

scholarly journals Electronic structure and optical properties of CsI under high pressure: a first-principles study

RSC Advances ◽  
2017 ◽  
Vol 7 (83) ◽  
pp. 52449-52455 ◽  
Author(s):  
Qiang Zhao ◽  
Zheng Zhang ◽  
Xiaoping Ouyang
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
Calculation Method ◽  
Density Functional ◽  
First Principles Calculation ◽  
Functional Theory ◽  
First Principles Study

We investigated the effects of high pressure on the electronic structure and optical properties of a CsI crystal through a first-principles calculation method based on density functional theory.

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