Structural and elastic properties of ZrN and HfN: ab initio study

2014 ◽  
Vol 92 (9) ◽  
pp. 1058-1061 ◽  
Author(s):  
Anurag Srivastava ◽  
Bhoopendra Dhar Diwan
Keyword(s):  
Elastic Properties ◽  
Density Functional ◽  
Zirconium Nitride ◽  
Energy Calculation ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Hafnium Nitride ◽  
Zinc Blende ◽  
The Density Functional Theory ◽  
The Stability

The present paper discusses the density functional theory based stability analysis of zirconium nitride and hafnium nitride in its rocksalt (B1), CsCl (B2), and zinc blende (B3) type phases. The ground state total energy calculation approach of the system has been used through the generalized gradient approximation parameterized with revised Perdew–Burke–Ernzerhof as exchange correlation functional. The present theoretical analysis confirms the stability trend of phases from most stable to less stable as B1 → B2 → B3. The study also reports the analysis of elastic properties of these nitrides in its most stable B1-type phase.

scholarly journals Structural, elastic, electronic and thermal properties of InAs: A study of functional density

2017 ◽  
Vol 26 (46) ◽  
Author(s):  
Víctor Mendoza-Estrada ◽  
Melissa Romero-Baños ◽  
Viviana Dovale-Farelo ◽  
William López-Pérez ◽  
Álvaro González-García ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Density Functional ◽  
Experimental Studies ◽  
Debye Model ◽  
Band Gap Energy ◽  
Functional Theory ◽  
Zinc Blende ◽  
The Density Functional Theory ◽  
The Stability ◽  
Experimental Values

In this research, first-principles calculations were carried out within the density functional theory (DFT) framework, using LDA and GGA, in order to study the structural, elastic, electronic and thermal properties of InAs in the zinc-blende structure. The results of the structural properties (a, B0, ) agree with the theoretical and experimental results reported by other authors. Additionally, the elastic properties, the elastic constants (C11, C12 and C44), the anisotropy coefficient (A) and the predicted speeds of the sound ( , , and ) are in agreement with the results reported by other authors. In contrast, the shear modulus (G), the Young's modulus (Y) and the Poisson's ratio (v) show some discrepancy with respect to the experimental values, although, the values obtained are reasonable. On the other hand, it is evident the tendency of the LDA and GGA approaches to underestimate the value of the band-gap energy in semiconductors. The thermal properties (V, , θD yCV) of InAs, calculated using the quasi-harmonic Debye model, are slightly sensitive as the temperature increases. According to the stability criteria and the negative value of the enthalpy of formation, InAs is mechanically and thermodynamically stable. Therefore, this work can be used as a future reference for theoretical and experimental studies based on InAs.

scholarly journals Structural and piezoelectric coefficients of AlP under pressure

2018 ◽  
Vol 6 (2) ◽  
pp. 53
Author(s):  
Salah Daoud ◽  
Rabie Mezouar ◽  
Abdelfateh Benmakhlouf
Keyword(s):  
Density Functional ◽  
Structural Parameters ◽  
Generalized Gradient ◽  
Aluminum Phosphide ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Generalized Gradient Approximation ◽  
Zinc Blende ◽  
Density Functional Perturbation Theory ◽  
The Density Functional Theory

The present work aims to investigate the structural parameters and the piezoelectric coefficients of cubic zinc-blende Aluminum phosphide (AlP) under high pressure up to 21 GPa, using plane wave-pseudopotential (PW-PP) approach in the framework of the density functional theory (DFT) and the density functional perturbation theory (DFPT) with the generalized gradient approximation (GGA) for the exchange-correlation functional. The results obtained are analyzed and compared with other data of the literature. The structural parameters and the piezoelectric coefficients calculated here agree well with other data of the literature. We found also that both the direct and converse piezoelectric coefficients increase with increasing pressure up to 21 GPa. 

Stability and Physicochemical Principles for Icosahedral Ti12X (X = Li to Xe) Clusters: A DFT Study

2008 ◽  
Vol 8 (5) ◽  
pp. 2475-2478
Author(s):  
M. Salazar-Villanueva ◽  
P. H. Hernandez Tejeda ◽  
J. F. Rivas-Silva ◽  
J. A. Ascencio
Keyword(s):  
Density Functional ◽  
Chemical Affinity ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Generalized Gradient Approximation ◽  
Stable Clusters ◽  
The Density Functional Theory ◽  
The Stability ◽  
Chemical Selectivity ◽  
Homo Lumo

Results about stability, electronic structure and characteristic electronic properties are reported for cluster structures based on icosahedra structure with a composition of Ti12X (X = Li to Xe) within the generalized gradient approximation of the density functional theory. It is demonstrated that several elements allow an improvement on the stability of Ti13 by a doping process where the central atoms is substituted. C, Si, P, Co, Ge, Ru and Te lead to the largest gain in energy, while the HOMO-LUMO maximum gap distinguishes to just C, Si, P and Te as the most probable to be found in experimental samples. The analysis included physicochemical study of the most stable clusters to predict chemical affinity and new properties. Results reported here are in agreement with partial studies of Ti12X but because of the considered elements, a new scope is open of possible application mainly in the fields as sensors, catalysis and medicine, where the chemical selectivity is an important parameter.

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.

scholarly journals First-Principle Study of Zinc Sulfide (Zinc Blende, Rock Salt and Wurtzite): Stability, Phase Transition and Structural Parameters

2020 ◽  
pp. 313-318
Author(s):  
Ibrahim Isah ◽  
Mustapha Isah
Keyword(s):  
Phase Transition ◽  
Zinc Sulfide ◽  
Rock Salt ◽  
Density Functional ◽  
Structural Parameters ◽  
First Principle ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Zinc Blende ◽  
The Stability

The research investigates the stability, phase transition and structural parameters of zinc sulfide (Zinc blende, Rock salt and Wurtzite) using first-principle. The study employs generalized gradient approximation (GGA) within density functional theory (DFT) in which ultra-soft pseudopotential (Zn.pbe-van.UPFb and S.pbe-van_bm.UPFc ) were used for both zinc and sulfide respectively. Self-consistent calculation was made using cut-off energies of 26Ry (~350 eV) and 180 Ry (~2450eV) for the cut-off wave function within the convergence accuracy of ~1mRy with respect to total energy and 0.5kbar in case of pressure. The results obtained show that Wurtzite is more stable because it has lowest energy among the three structures, there is transition from zinc blende to rock salt and from Wurtzite to rock salt with transition pressures of 17.5GPa and 16.9GPa respectively and all the three polymorphs are semi-conductors due to their band gap.

scholarly journals EOS parameters and elastic properties of cubic rock-salt BP

2019 ◽  
Vol 7 (1) ◽  
pp. 7
Author(s):  
Salah DAOUD
Keyword(s):  
Elastic Properties ◽  
Density Functional ◽  
Young Modulus ◽  
Generalized Gradient ◽  
Functional Theory ◽  
Boron Phosphide ◽  
Density Functional Perturbation Theory ◽  
The Density Functional Theory ◽  
Aggregate Material ◽  
Good Agreement

The present work aims to study the equation of state (EOS) under compression up to 100 GPa, and the elastic properties of cubic rocksalt Boron phosphide (BP) material. The EOS parameters and the elastic constants of our material of interest were predicted using plane wave-pseudopotential (PW-PP) approach in the framework of the density functional theory (DFT) and the density functional perturbation theory (DFPT) with the generalized gradient approximation (GGA) for the exchange-correlation functional. The Young modulus, the Poisson's ratio, the sound velocity, the Debye temperature and the melting temperature of the aggregate material were also presented. The results obtained are in general in good agreement compared to other data of the literature.

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

2012 ◽  
Vol 535-537 ◽  
pp. 1291-1294 ◽  
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.

Study of the Stability and Chemical Reactivity of a Series of Tetrazole Pyrimidine Hybrids by the Density Functional Theory Method (DFT)

2021 ◽  
Vol 37 (4) ◽  
pp. 805-812
Author(s):  
Ahissandonatien Ehouman ◽  
Adjoumanirodrigue Kouakou ◽  
Fatogoma Diarrassouba ◽  
Hakim Abdel Aziz Ouattara ◽  
Paulin Marius Niamien
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Molecular Descriptors ◽  
Chemical Reactivity ◽  
Density Functional Theory Method ◽  
Functional Theory ◽  
Reactivity Descriptors ◽  
The Density Functional Theory ◽  
The Stability ◽  
Global Reactivity Descriptors

Our theoretical study of stability and reactivity was carried out on six (06) molecules of a series of pyrimidine tetrazole hybrids (PTH) substituted with H, F, Cl, Br, OCH3 and CH3 atoms and groups of atoms using the density function theory (DFT). Analysis of the thermodynamic formation quantities confirmed the formation and existence of the series of molecules studied. Quantum chemical calculations at the B3LYP / 6-311G (d, p) level of theory determined molecular descriptors. Global reactivity descriptors were also determined and analyzed. Thus, the results showed that the compound PTH_1 is the most stable, and PTH_5 is the most reactive and nucleophilic. Similarly, the compound PTH_4 is the most electrophilic. The analysis of the local descriptors and the boundary molecular orbitals allowed us to identify the preferred atoms for electrophilic and nucleophilic attacks.

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).

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

2007 ◽  
Vol 21 (30) ◽  
pp. 5091-5098 ◽  
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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