High-Pressure elastic anisotropy and superconductivity of hafnium: a first-principles calculation

2020 ◽  
Author(s):  
Cheng-Bin Zhang ◽  
Wei-Dong Li ◽  
Ping Zhang ◽  
Bao-Tian Wang
Keyword(s):  
High Pressure ◽  
First Principles ◽  
Elastic Anisotropy ◽  
First Principles Calculation

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.

First-principles study of electronic structure, chemical bonding and elastic properties for new superconductor CaFeAs2

2017 ◽  
Vol 31 (02) ◽  
pp. 1650263
Author(s):  
J. G. Yan ◽  
Z. J. Chen ◽  
G. B. Xu ◽  
Z. Kuang ◽  
T. H. Chen ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Elastic Properties ◽  
Density Of States ◽  
First Principles ◽  
Elastic Anisotropy ◽  
First Principles Calculation ◽  
Hard Material ◽  
Dirac Cone ◽  
First Time ◽  
New Superconductor

Using first-principles calculation we investigated the structural, electronic and elastic properties of paramagnetic CaFeAs2. Our results indicated that the density of states (DOS) was dominated predominantly by Fe-3[Formula: see text] states at Fermi levels, and stronger hybridization exists between As1 and As1 atoms. Three hole pockets are formed at [Formula: see text] and Z points, and two electronic pockets are formed at A and E points. The Dirac cone-like bands appear near B and D points. For the first time we calculated the elastic properties and found that CaFeAs2 is a mechanically stable and moderately hard material, it has elastic anisotropy and brittleness, which agrees well with the bonding picture and the calculation of Debye temperature ([Formula: see text]).

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

scholarly journals New MAX Phase Superconductor Ti2GeC: A First-principles Study

2013 ◽  
Vol 6 (1) ◽  
pp. 11-27 ◽  
Author(s):  
M. A. Hadi ◽  
M. Roknuzzaman ◽  
F. Parvin ◽  
S. H. Naqib ◽  
A. K. M. A. Islam ◽  
...  
Keyword(s):  
Optical Properties ◽  
Thermodynamic Properties ◽  
Fermi Surface ◽  
Vickers Hardness ◽  
First Principles ◽  
Elastic Anisotropy ◽  
Debye Model ◽  
First Principles Calculation ◽  
Max Phase ◽  
Specific Heats

This is the first DFT-based first-principles prediction of the detailed optical and thermodynamic properties, including Vickers hardness and Fermi surface of 211 MAX phase Ti2GeC for which superconductivity (Tc~ 9.5 K) was reported very recently. The calculated structural properties are in excellent agreement with experiments. Our results on elastic parameters indicate a slight elastic anisotropy and brittleness of the compound. The chemical bonding is seen to be a combination of covalent, ionic and metallic nature. The rather stronger covalent bonding is responsible for its high Vickers hardness of 11.6 GPa. The investigated Fermi surface is formed mainly by the low-dispersive bands, which should be responsible for the presence of superconductivity in Ti2GeC. All the optical properties are evaluated and analyzed for two different polarization directions of incident photon. The temperature and pressure dependence of primitive cell volume, thermal expansion coefficient, specific heats, bulk modulus, and Debye temperature of Ti2GeC are derived from the quasi-harmonic Debye model with phononic effect and the various implications are discussed in details.  Keywords: First-principles calculation; Vickers hardness; Optical properties; Thermodynamic properties. © 2014 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. doi: http://dx.doi.org/10.3329/jsr.v6i1.16604 J. Sci. Res. 6 (1), 11-27 (2014)

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.

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