Investigations of Physical Properties of XTiH3 and Implications for Solid State Hydrogen Storage

2019 ◽  
Vol 74 (11) ◽  
pp. 1023-1030 ◽  
Author(s):  
Selgin AL
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Hydrogen Storage ◽  
Density Functional ◽  
Mechanical Stability ◽  
Mechanical Anisotropy ◽  
Electronic Band ◽  
Functional Theory ◽  
Electronic Band Structures ◽  
Formation Energies

AbstractThis study adopts density functional theory to predict and thoroughly investigate new types of perovskite compounds for solid state storage of hydrogen. CaTiH3 and MgTiH3 perovskite hydrides are chosen and investigated using density functional theory in terms of ground state properties, electronic, mechanical, and thermodynamic properties for solid state storage of hydrogen. Stability of compounds are verified by calculating formation energies. Several crucial parameters; elastic constants, bulk, Young, Shear modulus, and Cauchy pressures are computed and analysed in great detail. Mechanical stability evaluation indicated that both compounds are mechanically stable whereas MgTiH3 is ductile whilst CaTiH3 is a brittle material. In addition, mechanical anisotropy is analysed using 2D surfaces. Both compounds showed anisotropic behaviour in all directions except for linear compressibility. Electronic band structures and their corresponding density of states of compounds are obtained. The results indicate that both compounds have metallic nature. From the results presented here, it can be predicted that MgTiH3 is a better material for hydrogen storage with a gravimetric density of ∼4.01 wt %.

scholarly journals The Magnetic Band-Structures of Ordered PtxFe1−x, PtxCo1−x, and PtxNi1−x (x = 0.25, 0.50, and 0.75)

2020 ◽  
Vol 6 (4) ◽  
pp. 61
Author(s):  
Ian Shuttleworth
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
High Symmetry ◽  
Band Structures ◽  
Electronic Band ◽  
Functional Theory ◽  
Ni Alloys ◽  
Spin Polarized ◽  
Electronic Band Structures

The electronic band structures of the ordered L12 and L10 phases of the PtxM1−x (M = Fe, Co and Ni) alloys were investigated using spin-polarized density functional theory (DFT). The relative contributions of both itinerant (Stoner) and localized magnetism at the high-symmetry k-points were determined and discussed qualitatively. Significant directional effects were identified along the A and R directions of the L10 and L12 alloys, respectively, and are discussed in terms of charge channeling effects.

scholarly journals Evolution of Dirac Cone in Disclinated Graphene

2018 ◽  
Vol 57 (2) ◽  
pp. 137-142 ◽  
Author(s):  
M.A. Rozhkov ◽  
A.L. Kolesnikova ◽  
I. Hussainova ◽  
M.A. Kaliteevskii ◽  
T.S. Orlova ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Density Functional Theory ◽  
Band Structure ◽  
Density Functional ◽  
Md Simulation ◽  
Dirac Cone ◽  
Electronic Band ◽  
Functional Theory ◽  
Periodic Distribution ◽  
Electronic Band Structures

Abstract Graphene crystals, containing arrays of disclination defects, are modeled and their energies are calculated using molecular dynamics (MD) simulation technique. Two cases are analyzed in details: (i) pseudo-graphenes, which contain the alternating sign disclination ensembles and (ii) graphene with periodic distribution of disclination quadrupoles. Electronic band structures of disclinated graphene crystals are calculated in the framework of density functional theory (DFT) approach. The evolution of the Dirac cone and magnitude of band gap in the band structure reveal a dependence on the density of disclination quadrupoles and alternating sign disclinations. The electronic properties of graphene with disclination ensembles are discussed.

Systematic first principles calculations of the effects of stacking faults defects on the 4H-SiC band structure

2010 ◽  
Vol 1246 ◽  
Author(s):  
Massimo Camarda ◽  
pietro delugas ◽  
Andrea Canino ◽  
Andrea Severino ◽  
nicolo piluso ◽  
...  
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Stacking Faults ◽  
Perfect Crystal ◽  
First Principles Calculations ◽  
Electronic Band ◽  
Functional Theory ◽  
Experimental Findings ◽  
Electronic Band Structures ◽  
Formation Energies

AbstractShockley-type Stacking faults (SSF) in hexagonal Silicon Carbide polytypes have received considerable attention in recent years since it has been found that these defects are responsible for the degradation of forward I-V characteristics in p-i-n diodes. In order to extend the knowledge on these kind of defects and theoretically support experimental findings (specifically, photoluminescence spectral analysis), we have determined the Kohn-Sham electronic band structures, along the closed path Γ-M-K-Γ, using density functional theory. We have also determined the energies of the SSFs with respect to the perfect crystal finding that the (35) and (44) SSFs have unexpectedly low formation energies, for this reason we could expect these two defects to be easily generated/expanded either during the growth or post-growth process steps.

Electronic band structures of Ge1−xSnx semiconductors: A first-principles density functional theory study

2013 ◽  
Vol 113 (6) ◽  
pp. 063517 ◽  
Author(s):  
Ming-Hsien Lee ◽  
Po-Liang Liu ◽  
Yung-An Hong ◽  
Yen-Ting Chou ◽  
Jia-Yang Hong ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
First Principles ◽  
Density Functional ◽  
Density Functional Theory Study ◽  
Band Structures ◽  
Electronic Band ◽  
Functional Theory ◽  
Electronic Band Structures

scholarly journals Structural Analysis, Phase Stability, Electronic Band Structures, and Electric Transport Types of (Bi2)m(Bi2Te3)n by Density Functional Theory Calculations

2021 ◽  
Vol 11 (23) ◽  
pp. 11341
Author(s):  
Sungjin Park ◽  
Byungki Ryu ◽  
SuDong Park
Keyword(s):  
Density Functional Theory ◽  
Phase Stability ◽  
Thermoelectric Materials ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Electric Transport ◽  
Band Structures ◽  
Electronic Band ◽  
Functional Theory ◽  
Electronic Band Structures

Thermoelectric power generation is a promising candidate for automobile energy harvesting technologies because it is eco-friendly and durable owing to direct power conversion from automobile waste heat. Because Bi−Te systems are well-known thermoelectric materials, research on (Bi2)m(Bi2Te3)n homologous series can aid the development of efficient thermoelectric materials. However, to the best of our knowledge, (Bi2)m(Bi2Te3)n has been studied through experimental synthesis and measurements only. Therefore, we performed density functional theory calculations of nine members of (Bi2)m(Bi2Te3)n to investigate their structure, phase stability, and electronic band structures. From our calculations, although the total energies of all nine phases are slightly higher than their convex hulls, they can be metastable owing to their very small energy differences. The electric transport types of (Bi2)m(Bi2Te3)n do not change regardless of the exchange–correlation functionals, which cause tiny changes in the atomic structures, phase stabilities, and band structures. Additionally, only two phases (Bi8Te9, BiTe) became semimetallic or semiconducting depending on whether spin–orbit interactions were included in our calculations, and the electric transport types of the other phases were unchanged. As a result, it is expected that Bi2Te3, Bi8Te9, and BiTe are candidates for thermoelectric materials for automobile energy harvesting technologies because they are semiconducting.

Surface-dependent band structure variations and bond-level deviations of Cu2O

2021 ◽  
Author(s):  
Chih Shan Tan ◽  
Michael H. Huang
Keyword(s):  
Density Functional Theory ◽  
Band Structure ◽  
Dft Calculations ◽  
Density Functional ◽  
Band Structures ◽  
Electronic Band ◽  
Functional Theory ◽  
Electronic Band Structures

Density functional theory (DFT) calculations have been performed on 1 to 9 layers of Cu2O (100), (111), and (110) planes to further understand the electronic band structures and the origin...

Size dependent electronic band structures of β- and γ-graphyne nanotubes

RSC Advances ◽  
2015 ◽  
Vol 5 (98) ◽  
pp. 80118-80121 ◽  
Author(s):  
Baotao Kang ◽  
Jong Hun Moon ◽  
Jin Yong Lee
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Band Structures ◽  
Electronic Band ◽  
Functional Theory ◽  
Size Dependent ◽  
Electronic Band Structures

In the present paper, density functional theory calculations have been implemented by using Dmol3 to study the electronic band structures of β-graphyne nanotubes (βGyNTs) and γ-graphyne nanotubes (γGyNTs).

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