High-pressure plastic flow in silicon: A first-principles theoretical study

1993 ◽  
Vol 1 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Yu-Min Juan ◽  
Efthimios Kaxiras
Keyword(s):  
High Pressure ◽  
Plastic Flow ◽  
First Principles ◽  
Theoretical Study

scholarly journals First-Principles Calculations of High-Pressure Physical Properties of Ti0.5Ta0.5 Alloy

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 796
Author(s):  
Fang Yu ◽  
Yu Liu
Keyword(s):  
High Pressure ◽  
Physical Properties ◽  
First Principles ◽  
Theoretical Study ◽  
Applied Pressure ◽  
Lattice Parameter ◽  
Physical Parameters ◽  
First Principles Calculations ◽  
Analysis Method ◽  
Metallic Bond

In this paper, an in-depth theoretical study on some physical properties of Ti0.5Ta0.5 alloy with systematic symmetry under high pressure is conducted via first-principles calculations, and relevant physical parameters are calculated. The results demonstrate that the calculated parameters, including lattice parameter, elastic constants, and elastic moduli, fit well with available theoretical and experimental data when the Ti0.5Ta0.5 alloy is under T = 0 and P = 0 , indicating that the theoretical analysis method can effectively predict the physical properties of the Ti0.5Ta0.5 alloy. The microstructure and macroscopic physical properties of the alloy cannot be destroyed as the applied pressure ranges from 0 to 50GPa, but the phase transition of crystal structure may occur in the Ti0.5Ta0.5 alloy if the applied pressure continues to increase according to the TDOS curves and charge density diagram. The value of Young’s and shear modulus is maximized at P = 25   GPa . The anisotropy factors A ( 100 ) [ 001 ] and A ( 110 ) [ 001 ] are equal to 1, suggesting the Ti0.5Ta0.5 alloy is an isotropic material at 28 GPa, and the metallic bond is strengthened under high pressure. The present results provide helpful insights into the physical properties of Ti0.5Ta0.5 alloy.

Theoretical Study of High Pressure Metallic Hydrogen

1990 ◽  
Vol 193 ◽  
Author(s):  
Troy W. Barbee ◽  
Alberto García ◽  
Marvin L. Cohen
Keyword(s):  
High Pressure ◽  
Phase Transitions ◽  
Transition Temperature ◽  
First Principles ◽  
Theoretical Study ◽  
Hexagonal Phase ◽  
Temperature Phase ◽  
Superconducting Transition ◽  
Zero Temperature ◽  
Metallic Hydrogen

ABSTRACTA study of the zero temperature phase transitions in hydrogen under megabar pressures using a first-principles total-energy method is presented. An anisotropic primitive hexagonal phase is found to be particularly stable relative to other monatomic phases for pressures between 4 and 8 megabars. Calculations of the vibrational frequencies show that this phase is unstable with respect to a distortion tripling the unit cell along the c-axis. Results for this distorted hexagonal phase will be presented, including a calculation of its superconducting transition temperature Tc.

Theoretical Study of a new Transition Sequence in III-V Compounds: High-Pressure Phases of InSb

1990 ◽  
Vol 193 ◽  
Author(s):  
Alberto García ◽  
Marvin L. Cohen ◽  
S. B. Zhang
Keyword(s):  
High Pressure ◽  
Total Energy ◽  
First Principles ◽  
Theoretical Study ◽  
Hexagonal Phase ◽  
Structural Models ◽  
Zero Temperature ◽  
Transition Sequence ◽  
Transition Paths ◽  
Bcc Phase

ABSTRACTA detailed study of the pressure-induced phase transitions at zero temperature in InSb up to 40 GPa using a first-principles pseudopotential total-energy method is presented. In addition to InSb(I) (cubic) and (II) (polar β-Sn), we identify InSb(III) as a hexagonal phase (found earlier for GaSb) and (VI) as a polar bcc phase in agreement with recent experiments. New structural models, orthorhombic polar β-Sn and body-centered orthorhombic, are proposed as candidates for the InSb(IV) and (V) phases based on total-energy minimizations. These findings are compared with recent results for GaAs to illustrate the trends in transition paths among III-V compounds.

Role of dislocations in the bcc-hcp transition under high pressure: A first-principles approach in beryllium

2020 ◽  
Vol 4 (6) ◽  
Author(s):  
Vanessa Riffet ◽  
Bernard Amadon ◽  
Nicolas Bruzy ◽  
Christophe Denoual
Keyword(s):  
High Pressure ◽  
First Principles

57Fe Mössbauer isomer shift of pure iron and iron oxides at high pressure—An experimental and theoretical study

2021 ◽  
Vol 154 (21) ◽  
pp. 214104
Author(s):  
Jacques K. Desmarais ◽  
Wenli Bi ◽  
Jiyong Zhao ◽  
Michael H. Hu ◽  
Esen Alp ◽  
...  
Keyword(s):  
High Pressure ◽  
Isomer Shift ◽  
Iron Oxides ◽  
Pure Iron ◽  
Theoretical Study ◽  
57Fe Mössbauer ◽  
Mössbauer Isomer Shift

High-pressure structural phase transition and metallization in Ga2S3 under non-hydrostatic and hydrostatic conditions up to 36.4 GPa

2021 ◽  
Author(s):  
Linfei Yang ◽  
Jianjun Jiang ◽  
Lidong Dai ◽  
Haiying Hu ◽  
Meiling Hong ◽  
...  
Keyword(s):  
Phase Transition ◽  
Raman Spectroscopy ◽  
High Pressure ◽  
Structural Properties ◽  
Structural Phase Transition ◽  
First Principles ◽  
Theoretical Calculations ◽  
Structural Phase

The vibrational, electrical and structural properties of Ga2S3 were explored by Raman spectroscopy, EC measurements, HRTEM and First-principles theoretical calculations under different pressure environments up to 36.4 GPa.

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