First-principles investigations on structural, elastic and mechanical properties of BNxAs1−x ternary alloys

A systematic investigation of the structural optimization, elastic and mechanical properties of the BN[Formula: see text]As[Formula: see text] ternary alloys are reported in the present work using the density–functional theory with the generalized gradient approximation (GGA) of the exchange–correlation functional. Some of the constants which are used to analyze the properties including elastic constants and modulus, and some parameters describing the elastic anisotropy and Debye temperature are also calculated. Our calculations were performed to evaluate the equilibrium lattice constant and band structure compared with the available theoretical works. On the one hand, our results might be expected to provide a theoretical basis for future study of BN[Formula: see text]As[Formula: see text] alloys towards elastic or mechanical properties. On the other hand, we draw a conclusion that BN[Formula: see text]As[Formula: see text] alloys show direct bandgap when x equals 0.25, 0.5 or 0.75. We obtained the elastic modulus, Poisson’s ratio and universal anisotropic index which are used to demonstrate the elastic anisotropy of these alloys which is proved according to our calculations. Also, we calculated the Debye temperature to illustrate covalent interactions and obtained the lower limit of the thermal conductivity for further research.

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Pressure effect on the mechanical and electronic properties of orthorhombic-C20

Modern Physics Letters B ◽

10.1142/s0217984918503803 ◽

2018 ◽

Vol 32 (31) ◽

pp. 1850380 ◽

Cited By ~ 1

Author(s):

Jian-Li Ma ◽

Zhi-Fen Fu ◽

Qun Wei ◽

Peng Liu ◽

Jian-Ping Zhou

Keyword(s):

High Pressure ◽

Electronic Properties ◽

Debye Temperature ◽

Density Functional ◽

Superhard Material ◽

Elastic Anisotropy ◽

Systematic Investigation ◽

Functional Theory ◽

Temperature Changes ◽

The Density Functional Theory

A systematic investigation of structural, mechanical, elastic anisotropy and electronic properties of a recently reported novel superhard material orthorhombic [Formula: see text] ([Formula: see text]-[Formula: see text]) under pressure is performed utilizing the density functional theory in this work. The crystal structure parameters are obtained at zero as well as at high pressure. Pressure induced elastic constants [Formula: see text], polycrystalline aggregate elastic modulus [Formula: see text], [Formula: see text] ratio, and Debye temperature changes for [Formula: see text]-[Formula: see text] have been determined. The crystal elastic anisotropies of the ultra-incompressible [Formula: see text]-[Formula: see text] are investigated in the pressure range of 0–100 GPa. The Lyakhov–Oganov model is applied to predict the hardness as functions of pressure. The calculated results reveal that [Formula: see text]-[Formula: see text] possesses high elastic anisotropy under zero pressure and high pressure, and the hardness of [Formula: see text]-[Formula: see text] decreases with pressure, while the Debye temperature behaves with the opposite trend. The results of electronic structure indicate that [Formula: see text]-[Formula: see text] exhibits insulator characteristics, and the band gap increases with pressure. This work is expected to provide a useful guide for the future synthesis and application of [Formula: see text]-[Formula: see text].

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Elastic Properties of Orthorhombic YBa2Cu3O7 under Pressure

Crystals ◽

10.3390/cryst9100497 ◽

2019 ◽

Vol 9 (10) ◽

pp. 497 ◽

Cited By ~ 1

Author(s):

Cai Chen ◽

Lili Liu ◽

Yufeng Wen ◽

Youchang Jiang ◽

Liwan Chen

Keyword(s):

Thermal Conductivity ◽

Debye Temperature ◽

Elastic Constants ◽

Density Functional ◽

Elastic Anisotropy ◽

Elastic Stability ◽

Functional Theory ◽

Conductivity Increase ◽

Isotropic Pressure ◽

The Density Functional Theory

The pressure dependence of the lattice and elastic constants of the orthorhombic YBa 2 Cu 3 O 7 are firstly investigated using the first principles calculations based on the density functional theory. The calculated lattice parameters at 0 GPa are in agreement with the available experimental data. By the elastic stability criteria under isotropic pressure, it is predicted that YBa 2 Cu 3 O 7 with and orthorhombic structure is mechanically stable under pressure up to 100 GPa. On the basis of the elastic constants, Pugh’s modulus ratio, Poisson’s ratio, elastic anisotropy, Debye temperature, and the minimum thermal conductivity of YBa 2 Cu 3 O 7 under pressure up to 100 GPa are further investigated. It is found that its ductility, Debye temperature, and minimum thermal conductivity increase with pressure.

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Exploring the impact of hydrostatic pressure on the structural, electronic and mechanical properties of ZrNiPb half-Heusler alloy: A DFT approach

International Journal of Modern Physics B ◽

10.1142/s021797921850248x ◽

2018 ◽

Vol 32 (23) ◽

pp. 1850248

Author(s):

M. I. Babalola ◽

B. I. Adetunji ◽

B. E. Iyorzor ◽

A. Yaya

Keyword(s):

Mechanical Properties ◽

Heusler Alloy ◽

Poisson’S Ratio ◽

Density Functional ◽

Energy Gap ◽

Poisson's Ratio ◽

Generalized Gradient ◽

Functional Theory ◽

The Density Functional Theory ◽

The Impact

The structural, electronic, elastic and mechanical properties of ZrNiPb half-Heusler alloy under pressure ranging from 0 to 25 GPa have been studied using the density functional theory within the generalized gradient approximation (GGA). The results of ambient condition were in good agreement with the available theoretical and experimental data. Our electronic structure and density of state results show that ZrNiPb is an indirect bandgap semiconductor half-Heusler alloy with a narrow energy gap of 0.375 eV. Based on the calculated elastic constants (C[Formula: see text], C[Formula: see text] and C[Formula: see text]), Young’s modulus (E), Poisson’s ratio ([Formula: see text]), Shear modulus (G), Zener anisotropy factor (A) and brittle-ductile behaviors under pressure have been discussed. The calculated Poisson’s ratio shows that ZrNiPb undergoes a relatively small volume change during uniaxial deformation. We show that the chemical bonds in ZrNiPb are stronger due to the high value of C[Formula: see text].

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An Investigation of Half-Metallic Ferromagnets Behavior in Hg2CuTi-Type Heusler Alloy Ti2FeAl by Using GGA

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.535-537.1291 ◽

2012 ◽

Vol 535-537 ◽

pp. 1291-1294 ◽

Cited By ~ 2

Author(s):

Xiu De Yang ◽

Bo Wu ◽

Song Zhang

Keyword(s):

Density Functional Theory ◽

Heusler Alloy ◽

Density Functional ◽

Generalized Gradient ◽

Functional Theory ◽

Half Metallic ◽

Generalized Gradient Approximation ◽

Indirect Exchange ◽

The Density Functional Theory ◽

Direct Hybridization

By using generalized gradient approximation (GGA) scheme within the density functional theory (DFT), the electronic and magnetic properties of Hg2CuTi-type Heusler alloy Ti2FeAl were investigated. The results reveal that a 100% spin polarization appears at Fermi level (εF) in Ti2FeAl, and is maintained during lattice range of 5.1Å~6.2Å. Ti2FeAl is one of stable Half-Metallic Ferromagnets (HMF) with a spin-minority gap of 0.5 eV at εF and total magnetic moment of 1μB per unit cell. Our studies also indicate that the competition between RKKY-type indirect exchange and direct hybridization of d-electronic atoms plays a dominating role in determining the magnetism.

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Oxygen vacancy and doping atom effect on electronic structure and optical properties of Cd2SnO4

RSC Advances ◽

10.1039/c7ra10641f ◽

2018 ◽

Vol 8 (2) ◽

pp. 640-646 ◽

Cited By ~ 8

Author(s):

Mei Tang ◽

JiaXiang Shang ◽

Yue Zhang

Keyword(s):

Optical Properties ◽

Electronic Structure ◽

Oxygen Vacancy ◽

Density Functional ◽

Generalized Gradient ◽

Functional Theory ◽

The Density Functional Theory ◽

La Doped ◽

Doping Atom ◽

Atom Effect

The electronic structure and optical properties of oxygen vacancy and La-doped Cd2SnO4 were calculated using the plane-wave-based pseudopotential method based on the density functional theory (DFT) within the generalized gradient approximation (GGA).

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Computational Evidence Suggests That 1-chloroethanol May Be an Intermediate in the Thermal Decomposition of 2-chloroethanol into Acetaldehyde and HCl

10.26434/chemrxiv.7608857.v1 ◽

2019 ◽

Author(s):

Zoi Salta ◽

Agnie M. Kosmas ◽

Oscar Ventura ◽

Vincenzo Barone

Keyword(s):

Aqueous Solution ◽

Water Molecule ◽

Gas Phase ◽

Density Functional ◽

Water Molecules ◽

Functional Theory ◽

Direct Transformation ◽

The Density Functional Theory ◽

Successive Step ◽

The One

The dehalogenation of 2-chloroethanol (2ClEtOH) in gas phase with and without participation of catalytic water molecules has been investigated using methods rooted into the density functional theory. The well-known HCl elimination leading to vinyl alcohol (VA) was compared to the alternative elimination route towards oxirane and shown to be kinetically and thermodynamically more favorable. However, the isomerization of VA to acetaldehyde in the gas phase, in the absence of water, was shown to be kinetically and thermodynamically less favorable than the recombination of VA and HCl to form the isomeric 1-chloroethanol (1ClEtOH) species. This species is more stable than 2ClEtOH by about 6 kcal mol-1, and the reaction barrier is 22 kcal mol-1 vs 55 kcal mol-1 for the direct transformation of VA to acetaldehyde. In a successive step, 1ClEtOH can decompose directly to acetaldehyde and HCl with a lower barrier (29 kcal mol-1) than that of VA to the same products (55 kcal mol-1). The calculations were repeated using a single ancillary water molecule (W) in the complexes 2ClEtOH_W and 1ClEtOH_W. The latter adduct is now more stable than 2ClEtOH_W by about 8 kcal mol-1, implying that the water molecule increased the already higher stability of 1ClEtOH in the gas phase. However, this catalytic water molecule lowers dramatically the barrier for the interconversion of VA to acetaldehyde (from 55 to 6 kcal mol-1). This barrier is now smaller than the one for the conversion to 1ClEtOH (which also decreases, but not so much, from 22 to 12 kcal mol-1). Thus, it is concluded that while 1ClEtOH may be a plausible intermediate in the gas phase dehalogenation of 2ClEtOH, it is unlikely that it plays a major role in water complexes (or, by inference, aqueous solution). It is also shown that neither in the gas phase nor in the cluster with one water molecule, the oxirane path is competitive with the VA alcohol path.

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Structural, Elastic and Electronic Properties of γ˝ Phase Precipitate in Mg-Gd-Zn Alloy

Journal of the chemical society of pakistan ◽

10.52568/000826/jcsp/41.06.2019 ◽

2019 ◽

Vol 41 (6) ◽

pp. 932-932

Author(s):

Mengmeng Wu Mengmeng Wu ◽

Rongkai Pan Rongkai Pan ◽

Jilei Liang Jilei Liang ◽

Guohai Zhou Guohai Zhou ◽

Li Ma and Chunyu Zhang Li Ma and Chunyu Zhang

Keyword(s):

Density Functional ◽

Elastic Anisotropy ◽

Poisson Ratio ◽

Covalent Bond ◽

Generalized Gradient ◽

Electronic Density ◽

Functional Theory ◽

Full Relaxation ◽

Principle Density Functional Theory ◽

Zn Alloy

The γ˝ phase (Mg4GdZn) precipitate in Mg-Gd-Zn alloy was calculated via ﬁrst-principle density functional theory within the generalized gradient approximation. Through structure optimization of full relaxation, the lattice parameters were theoretically obtained, and the calculated Mg4GdZn is the most energetically stable in view of the formation energy. Independent elastic constants were also calculated, illustrating the calculated Mg4GdZn is mechanically stable. The shear modulus, polycrystalline bulk modulus, Poisson ratio, and Young’s modulus of Mg4GdZn were calculated via the Voigt-Reuss-Hill approximation. Elastic anisotropy and ductility were analyzed in details. Seen from their charge density distribution and electronic density of states, both metallic bond and covalent bond were found in Mg4GdZn.

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First-Principles Study of Ag3Sn, AgZn3 and Ag5Zn8 Intermetallic Compounds

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.871.254 ◽

2021 ◽

Vol 871 ◽

pp. 254-263

Author(s):

Zhan Cheng ◽

Guan Xing Zhang ◽

Wei Min Long ◽

Svitlana Maksymova ◽

Jian Xiu Liu

Keyword(s):

First Principles ◽

Density Functional ◽

Elastic Anisotropy ◽

Constant Density ◽

Mulliken Population ◽

Covalent Bonds ◽

Functional Theory ◽

The Density Functional Theory ◽

Anisotropy Index ◽

Ionic Bonds

The first-principles calculations by CASTEP program based on the density functional theory is applied to calculate the cohesive energy, enthalpy of formation, elastic constant, density of states and Mulliken population of Ag3Sn、AgZn3 and Ag5Zn8. Furthermore, the elastic properties, bonding characteristics, and intrinsic connections of different phases are investigated. The results show that Ag3Sn、AgZn3 and Ag5Zn8 have stability structural, plasticity characteristics and different degrees of elastic anisotropy; Ag3Sn is the most stable structural, has the strongest alloying ability and the best plasticity. AgZn3 is the most unstable structure, has the worst plasticity; The strength of Ag5Zn8 is strongest, AgZn3 has the weakest strength, the largest shear resistance, and the highest hardness. Ag5Zn8 has the maximum Anisotropy index and Ag3Sn has the minimum Anisotropy index. Ag3Sn、AgZn3 and Ag5Zn8 are all have covalent bonds and ionic bonds, the ionic bonds decrease in the order Ag3Sn>Ag5Zn8>AgZn3 and covalent bonds decreases in the order Ag5Zn8>Ag3Sn>AgZn3.

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STRUCTURE AND MAGNETIC PROPERTIES OF Co12X(X = Ni, Ag, Pt, Au) CLUSTERS

International Journal of Modern Physics B ◽

10.1142/s0217979207038241 ◽

2007 ◽

Vol 21 (30) ◽

pp. 5091-5098 ◽

Cited By ~ 4

Author(s):

Q. L. LU ◽

J. C. JIANG ◽

J. G. WAN ◽

G. H. WANG

Keyword(s):

Density Functional ◽

Magnetic Moments ◽

Stable Configuration ◽

Many Body ◽

Generalized Gradient ◽

Functional Theory ◽

Au Clusters ◽

The Density Functional Theory ◽

Ground State Structures ◽

Body Potential

The ground state structures of Co 12 X ( X = Ni , Ag , Pt , Au ) clusters are obtained by a genetic algorithm with a Gupta-like many-body potential, and further optimized using the density functional theory with generalized gradient approximation. The structures of Co 12 X have a slightly distorted icosahedral pattern. The X atom is on the surface for the most stable configuration. Their total magnetic moments are 0μ B , 3μ B , 21μ B , and 22μ B , respectively. The reasons for the reduction of magnetism of Co 12 X are discussed in detail.

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Compare Study of Electronic Structure, Chemical Bonding and Elastic Properties of Ti3AC2 (A=Al, Si, Sn) by First-Principles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.624.117 ◽

2012 ◽

Vol 624 ◽

pp. 117-121 ◽

Cited By ~ 1

Author(s):

Fan Jun Zeng ◽

Qing Lin Xia

Keyword(s):

Electronic Structure ◽

Elastic Properties ◽

Chemical Bonding ◽

Density Functional ◽

Elastic Anisotropy ◽

Hexagonal Phase ◽

Partial Density ◽

Generalized Gradient ◽

Functional Theory ◽

Compare Study

The electronic structure, chemical bonding and elastic properties of Ti3AC2 (A=Al, Si, Sn) were investigated by generalized gradient approximation (GGA) based on density functional theory (DFT). The calculated lattice parameters and equilibrium volumes are in good agreement with the available experimental data. The density of state (DOS) and partial density of states (PDOS) show that the DOS at the Fermi level (EF) is located at the bottom of a valley and originate mainly from the Ti-3d electrons. Population analyses suggest that there are strong covalent bonding in Ti1-C and Ti2-C atoms in Ti3AC2 (A=Al, Si, Sn). Single-crystal elasticity constants were calculated and the polycrystalline elastic modules were estimated according to Voigt, Reuss and Hill’s approximations (VRH). The Young’s modulus Y, Poisson’s ratio ν and BH/GH are also predicted. Results conclude that the hexagonal phase Ti3AC2 (A=Al, Si, Sn) are mechanical stable and behaves in a brittle manner. Polycrystalline elastic anisotropy coefficients AB and AG are also derived from polycrystalline bulk modulus B and shear modulus G.

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