Pressure Effect on the Structural, Elastic and Electronic Behaviors of Li3Bi: Ab Initio Study

2013 ◽  
Vol 641-642 ◽  
pp. 479-482 ◽  
Author(s):  
Xiao Xiao Sun
Keyword(s):  
Shear Modulus ◽  
Ab Initio ◽  
Electronic Properties ◽  
Young’S Modulus ◽  
First Principles ◽  
Pressure Effect ◽  
Young's Modulus ◽  
Lattice Parameters ◽  
First Principles Calculations ◽  
G Ratio

First principles calculations have been performed to investigate the elastic and electronic behaviors of Li3Bi as a function of pressure from 0 GPa to 100 GPa with a step 10 GPa. Our calculations indicate that the lattice parameters and volume of cubic Li3Bi decrease with the increasing pressure. Cubic Fm-3m structure of Li3Bi is more mechanically stable at pressures of up to 100 GPa. The calculated results of the bulk, shear, Young’s modulus, B/G ratio of Li3Bi as a function of pressure show that Li3Bi has higher bulk, shear modulus and better ductility at 0 GPa than 50 GPa. The analysis of electronic properties reveals that the covalent Bi-Li bonding plays an important role in hardness and incompressibility of Li3Bi.

Effects of Elements on Mechanical and Electronic Properties of Ag from First-Principles Calculations

2018 ◽  
Vol 775 ◽  
pp. 506-513
Author(s):  
Hai Guang Ruan ◽  
Fu Xiang Huang ◽  
Ming Jun Zhong ◽  
Bao An Wu ◽  
Hui Yi Tang ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Bulk Modulus ◽  
Electronic Properties ◽  
First Principles ◽  
Function Theory ◽  
Covalent Bond ◽  
Density Function Theory ◽  
First Principles Calculations ◽  
Covalent Bonds ◽  
G Ratio

The first-principles calculations were performed to research effects of elements X (Au, Be, Pd, Y, Ca, Cu, In and Zn) on mechanical and electronic properties of Ag with the density function theory (DFT). A supercell consisting of 107 atoms of Ag and one solute atom X was used. It was found that the bulk modulus of Ag dilute solutions were affected by the bulk modulus of pure alloying elements as well as their volume. The shear modulus G trend to decrease with increase of volume of Ag caused by alloying addition, but Ag-X covalent bond had positive correlation with shear modulus G. All of Ag107X alloys were ductility since theirs B/G ratio, Poisson's ratios ν were larger than 1.75 and 0.33, respectively. Comparing to other calculated Ag107X alloys, Ag107Be and Ag107Cu had the larger Vickers hardness, the value of which were 3.96GPa, 3.86GPa, respectively. There were not only metallic bonds (Ag-Ag) but also covalent bonds (Ag-X) in Ag107X alloys. The strong covalent bonds between Y, Zn, Ca and Ag were mainly caused by orbital hybridization between Y-5p orbital, Zn-3d orbital, Ca-3d orbitals and Ag-4d, 5s and 5p orbitals.

Mechanical degradation of graphene by epoxidation: insights from first-principles calculations

2015 ◽  
Vol 17 (29) ◽  
pp. 19484-19490 ◽  
Author(s):  
Qing Peng ◽  
Liang Han ◽  
Jie Lian ◽  
Xiaodong Wen ◽  
Sheng Liu ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
First Principles ◽  
Young's Modulus ◽  
Mechanical Degradation ◽  
First Principles Calculations

The in-plane Young's modulus decreases with the degree of epoxidation.

Tension-induced mechanical properties of stanene

2016 ◽  
Vol 30 (12) ◽  
pp. 1650146 ◽  
Author(s):  
Lele Tao ◽  
Chuanghua Yang ◽  
Liyuan Wu ◽  
Lihong Han ◽  
Yuxin Song ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Elastic Constants ◽  
First Principles ◽  
Young's Modulus ◽  
Poisson Ratio ◽  
Group Iv ◽  
First Principles Calculations ◽  
Stress Strain Relation ◽  
Group Iv Elements ◽  
Internal Atom

In this paper, elastic properties of stanene under equiaxial or uniaxial tensions along armchair and zigzag directions are investigated by first-principles calculations. The stress–strain relation is calculated and the relaxation of the internal atom positions is analyzed. The high-order elastic constants are calculated by fitting the polynomial expressions. The Young’s modulus and Poisson ratio of the stanene is calculated to be 24.14 N/m and 0.39 N/m, respectively. The stanene exhibits lower Young’s modulus than those of the proceeding group IV elements, which is attributed to the smaller [Formula: see text]–[Formula: see text] bond energy in stanene than those of silicene and germanene. Calculated values of ultimate stresses and strains, second-order elastic constants (SOCEs) and the in-plane Young’s modulus are all positive. It proves that stanene is mechanically stable.

Electronic and magnetic properties of BN nanosheet superlattices: First-principles calculations

2018 ◽  
Vol 32 (31) ◽  
pp. 1850348
Author(s):  
Xiao-Qin Feng ◽  
Hong-Xia Lu ◽  
Jian-Ming Jia ◽  
Chang-Shun Wang
Keyword(s):  
Magnetic Properties ◽  
Boron Nitride ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Electronic Properties ◽  
First Principles ◽  
First Principles Calculations ◽  
Electronic And Magnetic Properties ◽  
Boron Nitride Nanosheet

Systematic ab initio calculations reveal that the electronic and magnetic properties are modified by superlattices of zigzag and armchair Boron nitride nanosheet (BNNS). Superlattices are constructed by partially hydrogenated B and N atoms of BNNS. The results show that only no more than half N atoms hydrogenated superlattices are antiferromagnetic. The electronic properties of zigzag BN nanosheet superlattices depend on the degree of hydrogenation of N atoms sensitively. As a result, changing the degree of hydrogenation of N atoms results in the transition from semiconductor to metal.

scholarly journals The Mechanical Properties and Elastic Anisotropies of Cubic Ni3Al from First Principles Calculations

Crystals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 307 ◽  
Author(s):  
Xinghe Luan ◽  
Hongbo Qin ◽  
Fengmei Liu ◽  
Zongbei Dai ◽  
Yaoyong Yi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Young’S Modulus ◽  
First Principles ◽  
Poisson’S Ratio ◽  
Density Functional ◽  
Young's Modulus ◽  
Small Deviation ◽  
Poisson's Ratio

Ni3Al-based superalloys have excellent mechanical properties which have been widely used in civilian and military fields. In this study, the mechanical properties of the face-centred cubic structure Ni3Al were investigated by a first principles study based on density functional theory (DFT), and the generalized gradient approximation (GGA) was used as the exchange-correlation function. The bulk modulus, Young’s modulus, shear modulus and Poisson’s ratio of Ni3Al polycrystal were calculated by Voigt-Reuss approximation method, which are in good agreement with the existing experimental values. Moreover, directional dependences of bulk modulus, Young’s modulus, shear modulus and Poisson’s ratio of Ni3Al single crystal were explored. In addition, the thermodynamic properties (e.g., Debye temperature) of Ni3Al were investigated based on the calculated elastic constants, indicating an improved accuracy in this study, verified with a small deviation from the previous experimental value.

scholarly journals Structural and electronic properties of boron- bismuth compound under pressure

2016 ◽  
Vol 4 (1) ◽  
pp. 1 ◽  
Author(s):  
Salah Daoud ◽  
Noudjoud Labgaa
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Pressure Effect ◽  
Local Density ◽  
Band Gaps ◽  
First Principles Calculations ◽  
Density Func Tional Theory ◽  
Exchange Correlation ◽  
Bismuth Compound ◽  
Structural And Electronic Properties

<p>In the present work, we report first principles calculations of the pressure effect on the structural and electronic properties of Boron- Bismuth (BBi) compound in its zincblende phase. The pseudopotential plane wave (PPW) method in the framework of the density func-tional theory (DFT) within the local density approximation for the exchange-correlation functional, and the Hartwigzen-Goedecker-Hutter (HGH) scheme for the pseudopotential were used in the calculation. The unit cell volume, the molecular and crystal densities, the equation of state and also the linear and quadratic pressure coefficients of the energy band-gaps are investigated.</p>

First-principles calculations for mechanical and electronic features of strained GaP nanowires

2017 ◽  
Vol 28 (03) ◽  
pp. 1750039 ◽  
Author(s):  
Rezek Mohammad ◽  
Şenay Katırcıoğlu
Keyword(s):  
Band Gap ◽  
Young’S Modulus ◽  
First Principles ◽  
Energy Band ◽  
Density Functional ◽  
Young's Modulus ◽  
First Principles Calculations ◽  
Effective Electron ◽  
Young’S Moduli ◽  
Effective Carrier

The mechanical and electronic properties of GaP nanowires are investigated by computing the Young’s modulus, Poisson’s ratio, energy band gap and effective carrier masses using first-principles calculations based on density functional theory. The wurtzite structural nanowires with diameters upper limited to [Formula: see text][Formula: see text]Å are strained by uniaxial strains in the range of [Formula: see text]–[Formula: see text]. The Young’s moduli of nanowires are found to be decreased with increase of the size in the direction of the Young’s modulus of the bulk GaP. The Poisson’s effect is determined to be stronger in GaP nanowires than in the bulk. The energy band gaps of the unstrained and strained nanowires are obtained to be enlarged with decrease of the size due to the quantum size effect. The confinement effect is found larger in the compressed nanowires than in the stretched ones. All the unstrained nanowires except the largest one are indirect band gap materials. Indirect to direct band gap transition is determined to be size and strain dependent. The effective carrier masses in all unstrained nanowires are found small compared to the ones in the bulk GaP. The effective electron and hole masses are obtained to be modulated in nanowires of this work by the compressive and both compressive/tensile strains, respectively.

First-Principles Study of Structural, Mechanical, and Thermodynamic Properties of Refractory Metals (Rh, Ir, W, Ta, Nb, Mo, Re, and Os)

2020 ◽  
Vol 993 ◽  
pp. 1017-1030
Author(s):  
Ying Jie Sun ◽  
Kai Xiong ◽  
Zong Bo Li ◽  
Shun Meng Zhang ◽  
Yong Mao
Keyword(s):  
Thermodynamic Properties ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Young’S Modulus ◽  
First Principles ◽  
Elastic Anisotropy ◽  
Young's Modulus ◽  
Refractory Metals ◽  
Body Centered Cubic ◽  
Cubic Metals

The structural, mechanical, and thermodynamic properties of refractory metals Rh, Ir, W, Ta, Nb, Mo, Re, and Os have been systematically investigated by first-principles calculations based on density functional theory. Comparative studies reveal that Young's modulus (E = 636.42 GPa), shear modulus (G = 256.81 GPa), bulk modulus (B = 406.55 GPa), and microhardness (H = 44.69 GPa) of hexagonal Os are the highest, which reveals Os has the best overall mechanical properties. The body-centered cubic Nb has the smallest Young's modulus (E = 94.76 GPa), shear modulus (G = 33.62 GPa), bulk modulus (B = 174.50 GPa), and hardness (H = 2.04 GPa). Based on the ratio of bulk to shear modulus, it is judged that Rh, Ir, and Os are brittle materials (B/G < 1.75), and Nb, Ta, Mo, W, and Re exhibit ductile (B/G > 1.75). The elastic anisotropy has also been discussed by plotting both the 3D contours and the 2D planar projections of Young's modulus. For the face-centered cubic metals Rh and Ir and hexagonal close-packed metals Re and Os, the 3D contours of the Young's modulus are very similar, whereas body-centered cubic metals Ta, W, Nb, and Mo exhibit significant difference in elastic anisotropy. The thermodynamic calculations show that Debye temperature and minimum thermal conductivity decreases along Rh, Os, Mo, Ir, Re, W, Ta, Nb sequence. Furthermore, the results can be used as a general guidance for the design and development of high temperature refractory alloy system.

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