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

2012 ◽  
Vol 624 ◽  
pp. 117-121 ◽  
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.

First Principles Investigation of Electronic Structure, Chemical Bonding, Elastic and Optical Properties of Novel Rhenium Nitrides

2012 ◽  
Vol 512-515 ◽  
pp. 883-889
Author(s):  
Qing Lin Xia ◽  
Liu Xian Pan ◽  
Yuan Dong Peng ◽  
Li Ya Li ◽  
Hong Zhong Wang ◽  
...  
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Density Of States ◽  
Chemical Bonding ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Hexagonal Phase ◽  
Partial Density

we investigate the electronic structure, chemical bonding, optical and elastic properties of the novel rhenium nitrides, hexagonal phase re3n and re2n by using density-functional theory (dft) within generalized gradient approximation (gga). the calculated equilibrium lattice constants of both re3n and re2n are in reasonable agreement with the experimental results. the band structure along the higher symmetry axes in the Brillouin zone, the density of states (dos) and the partial density of states (pdos) are presented. the calculated energy band structures and dos show that re3n and re2n are metal compounds. The dos and pdos show that the dos at the fermi level (ef) is located at the bottom of a valley and originate mainly from the 5d electrons of re. population analyses suggest that the chemical bonding in re3n and re2n has predominantly covalent character with mixed covalent and ionic characteristics. the dielectric function, reflectivity, absorption coefficient, refractive index, electron energy-loss function and optical conductivity are presented in an energy range for discussing the optical properties of re3n and re2n. basic mechanical properties, such as elastic constants cij, bulk modulus b and shear modulus g are calculated. The young’s modulus e, poisson's ratio ν and bh/gh are also predicted. results conclude that the hexagonal phase re3n and re2n are mechanical stable and behaves in a ductile manner. polycrystalline elastic anisotropy is also derived from polycrystalline bulk modulus b and shear modulus g.

First-Principles Study of Electronic Structure and Elastic Properties of Si Doping Ti3Al1-xSixC2 Solid Solutions

2012 ◽  
Vol 624 ◽  
pp. 122-126 ◽  
Author(s):  
Fan Jun Zeng ◽  
Qing Lin Xia
Keyword(s):  
Electronic Structure ◽  
Elastic Properties ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Poisson Ratio ◽  
Generalized Gradient ◽  
Virtual Crystal Approximation ◽  
Functional Theory ◽  
Si Doping ◽  
Elastic Modules

The electronic structure and elastic properties of Si doping Ti3Al1-xSixC2 (x=0-1) were studied by generalized gradient approximation (GGA) based on density functional theory (DFT) and virtual crystal approximation (VCA). The calculated lattice parameters and equilibrium volumes are in good agreement with the available experimental data. The density of state (DOS) shows that the DOS at the Fermi level (EF) is located at the bottom of a valley. Single-crystal elastic constants were calculated and the polycrystalline elastic modules were estimated according to Voigt, Reuss and Hill’s approximations (VRH). The results show that the bulk modules increase monotonously and the Poisson ratio v as well as BH and BG increase first and then decrease with the increasing of the doping Si. The Passion ratio v and BH/GH indicate that Ti3Al1-xSixC2 (x=0-1) are brittle compounds. Polycrystalline elastic anisotropy coefficients AB and AG were also derived and are very small.

scholarly journals Structural, electronic, and elastic properties of Tetragonal Sr0.5Be0.5TiO3: Ab-initio calculation.

2021 ◽  
Vol 67 (2 Mar-Apr) ◽  
pp. 299
Author(s):  
M. Tedjani
Keyword(s):  
Elastic Properties ◽  
Density Functional ◽  
Local Density ◽  
Partial Density ◽  
Full Potential ◽  
Generalized Gradient ◽  
Functional Theory ◽  
The Stability ◽  
First Time ◽  
Linearized Augmented Plane Wave

In this theoretical study, we presents  for the first time, to the best of our knowledge, the structural, electronic and elastic properties of perovskite Sr0.5Be0.5TiO3 type structure (Tetragonal), P4/mmm, space group, 123.using full potential linearized augmented plane wave (FP-LAPW) method on the basis of density functional theory (DFT) integrated in the Wien2k code . The generalized gradient approximation (GGA-PBEsol) and local density approximation has been used for the exchange correlation potential .The electronic properties represented by the band structure (BS) and DOS as well as the (PDOS) partial density of states, allowed to obtain  semiconductor compound, which have been calculated with mBJ approximation. The elastic constants were reported and we verified the stability conditions of our materials elastically. These theoretical results open the way for experimental and other theoretical studies of this compound.

Electronic Structure Of (AgSb)xPbn-2xTen

2003 ◽  
Vol 793 ◽  
Author(s):  
Daniel I Bilc ◽  
S.D. Mahanti ◽  
M.G. Kanatzidis
Keyword(s):  
Electronic Structure ◽  
Ab Initio ◽  
Density Functional ◽  
Full Potential ◽  
Generalized Gradient ◽  
Two Component System ◽  
Functional Theory ◽  
Covalent Interaction ◽  
Salt Structure ◽  
Linearized Augmented Plane Wave

ABSTRACTComplex quaternary chalcogenides (AgSb)xPbn-2xTen (0<x<n/2) are thought to be narrow band-gap semiconductors which are very good candidates for room and high temperature thermoelectric applications. These systems form in the rock-salt structure similar to the well known two component system PbTe (x=0). In these systems Ag and Sb occupy Pb sites randomly although there is some evidence of short-range order. To gain insights into the electronic structure of these compounds, we have performed electronic structure calculations in AgSbTe2 (x=n/2). These calculations were carried out within ab initio density functional theory (DFT) using full potential linearized augmented plane wave (LAPW) method. The generalized gradient approximation (GGA) was used to treat the exchange and correlation potential. Spinorbit interaction (SOI) was incorporated using a second variational procedure. Since it is difficult to treat disorder in ab initio calculations, we have used several ordered structures for AgSbTe2. All these structures show semimetallic behavior with a pseudogap near the Fermi energy. Te and Sb p orbitals, which are close in energy, hybridize rather strongly indicating a covalent interaction between Te and Sb atoms.

Electronic structure of cubic BaTbO3 from first-principles pseudopotential calculations

2006 ◽  
Vol 84 (2) ◽  
pp. 115-120 ◽  
Author(s):  
G Y Gao ◽  
K L Yao ◽  
Z L Liu
Keyword(s):  
Electronic Structure ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Pseudopotential Calculations ◽  
Correlation Potential ◽  
Density Contour

First-principles calculations of the electronic structure are performed for cubic BaTbO3 using the plane-wave pseudopotential method within the framework of density functional theory and using the generalized gradient approximation for the exchange-correlation potential. Our calculations show that cubic BaTbO3 is metallic, and that this metallic character is mainly governed by the Tb 4f electrons and the hybridization between the Tb 5d and O 2p states. From the analysis of the density of states, band structure, and charge density contour, we find that the chemical bonding between Tb and O is covalent while that between Ba and TbO3 is ionic. PACS Nos.: 71.15.Mb, 71.20.-b

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

RSC Advances ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 640-646 ◽  
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).

scholarly journals Density functional theory study of electronic properties of Bi2Se3 and Bi2Te3

2017 ◽  
Vol 12 (3) ◽  
Author(s):  
Abdullahi Lawal ◽  
Amiruddin Shaari
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Topological Insulators ◽  
Van Der Waals Interactions ◽  
Partial Density ◽  
Total Density ◽  
Density Of State ◽  
Generalized Gradient ◽  
Linear Dispersion ◽  
Functional Theory

Topological insulators are layered materials via van der Waals interactions with hexagonal unit cell similar to that of graphene. The exciting features of Bi2Se3 and Bi2Te3 topological insulators their zero band gap surface states exhibiting linear dispersion at the Fermi energy. We present here first principles study pertaining to electronics properties of Bi2Se3 and Bi2Te3 compound with and without spin-orbit interaction using density functional theory (DFT). Total density of state (DOS), partial density of state (PDOS) and band structure where determined by Quantum-Espresso simulation package which uses plane wave basis and pseudopotential for the core electrons, while treating exchange-correlation potential with generalized gradient approximation (GGA). From our computations, the obtained results were found to be consistent with the available experimental results. 

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

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.

Ab-initio thermodynamic and elastic properties of AlNi and AlNi3 intermetallic compounds

2018 ◽  
Vol 32 (11) ◽  
pp. 1850129 ◽  
Author(s):  
Shahram Yalameha ◽  
Aminollah Vaez
Keyword(s):  
Intermetallic Compounds ◽  
Elastic Properties ◽  
Density Functional ◽  
Full Potential ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Augmented Plane Wave ◽  
Wide Range ◽  
Computational Data ◽  
Linearized Augmented Plane Wave

In this paper, thermodynamic and elastic properties of the AlNi and AlNi3 were investigated using density functional theory (DFT). The full-potential linearized augmented plane-wave (APW) in the framework of the generalized gradient approximation as used as implemented in the Wien2k package. The temperature dependence of thermal expansion coefficient, bulk modulus and heat capacity in a wide range of temperature (0–1600 K) were investigated. The calculated elastic properties of the compounds show that both intermetallic compounds of AlNi and AlNi3 have surprisingly negative Poisson’s ratio (NPR). The results were compared with other experimental and computational data.

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