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]).

Structural and elastic properties of Cu6Sn5 and Cu3Snfrom first-principles calculations

2009 ◽  
Vol 24 (7) ◽  
pp. 2361-2372 ◽  
Author(s):  
Jiunn Chen ◽  
Yi-Shao Lai ◽  
Ping-Feng Yang ◽  
Chung-Yuan Ren ◽  
Di-Jing Huang
Keyword(s):  
Electronic Structure ◽  
Elastic Modulus ◽  
Elastic Properties ◽  
First Principles ◽  
Elastic Anisotropy ◽  
Lattice Structure ◽  
Elastic Stiffness ◽  
First Principles Calculations ◽  
Atomic Lattice ◽  
Microstructure Effect

We investigated the elastic properties of two tin-copper crystalline phases, the η′-Cu6Sn5 and ε-Cu3Sn, which are often encountered in microelectronic packaging applications. The full elastic stiffness of both phases is determined based on strain-energy relations using first-principles calculations. The computed results show the elastic anisotropy of both phases that cannot be resolved from experiments. Our results, suggesting both phases have the greatest stiffness along the c direction, particularly showed the unique in-plane elastic anisotropy associated with the lattice modulation of the Cu3Sn superstructure. The polycrystalline moduli obtained using the Voigt-Reuss scheme are 125.98 GPa for Cu6Sn5 and 134.16 GPa for Cu3Sn. Our data analysis indicates that the smaller elastic moduli of Cu6Sn5 are attributed to the direct Sn–Sn bond in Cu6Sn5. We reassert the elastic modulus and hardness of both phases using the nanoindentation experiment for our calculation benchmark. Interestingly, the computed polycrystalline elastic modulus of Cu6Sn5 seems to be overestimated, whereas that of Cu3Sn falls nicely in the range of reported data. Based on the observations, the elastic modulus of Cu6Sn5 obtained from nanoindentation tests admit the microstructure effect that is absent for Cu3Sn is concluded. Our analysis of electronic structure shows that the intrinsic hardness and elastic modulus of both phases are dominated by electronic structure and atomic lattice structure, respectively.

scholarly journals First-principles calculations of electronic structure and optical and elastic properties of the novel ABX3-type LaWN3 perovskite structure

RSC Advances ◽  
2020 ◽  
Vol 10 (29) ◽  
pp. 17317-17326
Author(s):  
Xing Liu ◽  
Jia Fu ◽  
Guangming Chen
Keyword(s):  
Electronic Structure ◽  
Elastic Properties ◽  
First Principles ◽  
Perovskite Structure ◽  
First Principles Calculation ◽  
The Novel ◽  
First Principles Calculations ◽  
Material Genome Initiative

Using first-principles calculation, the stable R3c LaWN3 as a new ABX3-type advanced perovskite structure is designed in the plan of the material genome initiative (MGI), which helps to widen the nowadays nitride perovskite material's application.

scholarly journals Anisotropic elastic properties of FexB (x = 1, 2, 3) under pressure. First-principles study

2016 ◽  
Vol 34 (3) ◽  
pp. 503-516 ◽  
Author(s):  
A. Gueddouh ◽  
B. Bentria ◽  
Y. Bourourou ◽  
S. Maabed
Keyword(s):  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Poisson Ratio ◽  
Pressure Effects ◽  
Mechanical Anisotropy ◽  
First Principles Calculation ◽  
Young’S Moduli ◽  
Anisotropic Elastic

AbstractSpin-polarization (SP) and pressure effects have been used to better clarify and understand anisotropic elastic properties of Fe-B intermetallic compounds using the first-principles calculation with generalized gradient approximation (GGA) within the plane-wave pseudopotential density functional theory. Elastic properties, including bulk, shear and Young’s moduli as well as Poisson ratio were obtained by Voigt-Reuss-Hill approximation. All studied Fe-B compounds were mechanically stable. The brittle and ductile properties were discussed using bulk to shear moduli ratio (B/G) of the studied structures in the pressure range of 0 GPa to 90 GPa in order to predict the critical pressure of phase transition from ferromagnetic (FM) to nonmagnetic (NM) state. Mechanical anisotropy in both cases was discussed by calculating different anisotropic indexes and factors. We have plotted three-dimensional (3D) surfaces and planar contours of the bulk and Young’s moduli of FexB (x = 1, 2, 3) compounds for some crystallographic planes, (1 0 0), (0 1 0) and (0 0 1), to reveal their elastic anisotropy. On the basis of anisotropic elastic properties the easy and hard axes of magnetization for the three studied compounds were predicted.

First-principles study on the electronic structure and elastic properties of Mo2NiB2 doped with V

2018 ◽  
Vol 32 (10) ◽  
pp. 1850065 ◽  
Author(s):  
Jinming Li ◽  
Xiaobo Li ◽  
Haiyun Gao ◽  
Dian Peng
Keyword(s):  
Electronic Structure ◽  
Elastic Properties ◽  
Density Of States ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Formation Enthalpy ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Ternary Boride

The content of this study is to analyze the electronic structure and elastic properties that the different structures of Mo2NiB2 and doping with V of the tetragonal M3B2 (Mo2Ni[Formula: see text]V[Formula: see text]B2 and Mo[Formula: see text]Ni[Formula: see text]V[Formula: see text]B2) (x = 0.25, 0.5, 0.75 and y = 0.125, 0.25, 0.375) by first-principles calculations based on density functional theory (DFT) combined with the projection-plus-wave method. But the calculated formation energy shows that V atoms prefer to substitute the Mo and Ni atoms of the tetragonal Mo2NiB2. Moreover, with the increase of V content, the formation enthalpy of tetragonal Mo2NiB2 is reduced, and the formation enthalpy of Mo[Formula: see text]Ni[Formula: see text]V[Formula: see text]B2 is the least as −53.23 kJ/mol. The calculated elastic constant suffices the condition of mechanical stability, indicate that they are stable. The calculated elastic modulus illustrates that Mo2NiB2 having better mechanical properties when V elements are at Mo and Ni sites instead of Ni sites. The calculated and analyzed density of states of Mo[Formula: see text]Ni[Formula: see text]V[Formula: see text]B2 has the smallest the density of states at the Fermi level indicating that it has the more stable structure. For the theoretical analysis of the first-principles calculations, the addition of 15 atom% of the V and V doping modes of Mo and Ni are preferentially replaced by V atoms of Mo2NiB2 ternary boride has the best performance.

scholarly journals Structural, Elastic, and Electronic Properties of ReB2: A First-Principles Calculation

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
Run Long ◽  
Ying Dai ◽  
Hao Jin ◽  
Baibiao Huang
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Structural Parameters ◽  
Elastic Stiffness ◽  
First Principles Calculation ◽  
Hard Material ◽  
Functional Theory ◽  
Calculated Equilibrium

The structural, elastic, and electronic properties of the hard material ReB2 have been investigated by means of density functional theory. The calculated equilibrium structural parameters of ReB2 are in agreement with the experimental results. Our result of bulk modulus shows that it is a low compressible material. Furthermore, the elastic anisotropy is discussed by investigating the elastic stiffness constants. The charge density and the electronic properties indicate that the covalent bonding of Re-B and B-B plays an important role in formation of a hard material. The good metallicity and hardness of ReB2 might serve as hard conductors.

First-principles study of (Ti5−xMgx)Si3 phases with the hexagonal D88 structure: Elastic properties and electronic structure

2012 ◽  
Vol 54 ◽  
pp. 287-292 ◽  
Author(s):  
Xiao-Jun Chen ◽  
Meng-Xue Zeng ◽  
Ren-Nian Wang ◽  
Zhou-Sheng Mo ◽  
Bi-Yu Tang ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Elastic Properties ◽  
First Principles ◽  
First Principles Study
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