Structural, electronic and elastic properties of the B2-ScM (M =Au, Hg and Tl) intermetallic compounds: Ab initio calculations

2015 ◽  
Vol 04 (04) ◽  
pp. 1550020
Author(s):  
Ahmad A. Mousa ◽  
Jamil M. Khalifeh
Keyword(s):  
Mechanical Properties ◽  
Bulk Modulus ◽  
Intermetallic Compounds ◽  
Elastic Constants ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic Band

Structural, electronic, elastic and mechanical properties of ScM (M[Formula: see text][Formula: see text][Formula: see text]Au, Hg and Tl) intermetallic compounds are studied using the full potential-linearized augmented plane wave (FP-LAPW) method based on the density functional theory (DFT), within the generalized gradient approximation (GGA) and the local density approximation (LDA) to the exchange-correlation approximation energy as implemented in the Wien2k code. The ground state properties including lattice parameters, bulk modulus and elastic constants were all computed and compared with the available previous theoretical and experimental results. The lattice constant was found to increase in contrast to the bulk modulus which was found to decrease with every substitution of the cation (M) starting from Au till Tl in ScM. Both the electronic band structure and density-of-states (DOS) calculations show that these compounds possess metallic properties. The calculated elastic constants ([Formula: see text], [Formula: see text] and [Formula: see text] confirmed the elastic stability of the ScM compounds in the B2-phase. The mechanical properties and ductile behaviors of these compounds are also predicted based on the calculated elastic constants.

Ab initio study of structural, mechanical, thermal and electronic properties of perovskites Sr(Li,Pd)H3

2016 ◽  
Vol 30 (04) ◽  
pp. 1650003 ◽  
Author(s):  
S. Benlamari ◽  
S. Amara Korba ◽  
S. Lakel ◽  
H. Meradji ◽  
S. Ghemid ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Electronic Properties ◽  
Elastic Constants ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Velocity Variation ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic Band

The structural, elastic, thermal and electronic properties of perovskite hydrides SrLiH3 and SrPdH3 have been investigated using the all-electron full-potential linear augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). For the exchange-correlation potential, local-density approximation (LDA) and generalized gradient approximation (GGA) have been used to calculate theoretical lattice parameters, bulk modulus, and its pressure derivative. The present results are in good agreement with available theoretical and experimental data. The three independent elastic constants [Formula: see text], [Formula: see text] and [Formula: see text] are also reported. From electronic band structure and density of states (DOSs), it is found that SrLiH3 is an insulator characterized by an indirect gap of 3.48 eV, while SrPdH3 is metallic with a calculated DOSs at Fermi energy of 0.745 states/eV-unit cell. Poisson’s ratio [Formula: see text], Young’s modulus (E), shear modulus (G), anisotropy factor (A), average sound velocities [Formula: see text] and density [Formula: see text] of these compounds are also estimated for the first time. The Debye temperature is deduced from the average sound velocity. Variation of elastic constants and bulk modulus of these compounds as a function of pressure is also reported. Pressure and thermal effects on some macroscopic properties are predicted using the quasi-harmonic Debye model.

DFT-BASEDAB INITIOSTUDY OF THE ELECTRONIC AND OPTICAL PROPERTIES OF CESIUM BASED FLUORO-PEROVSKITECsMF3(M = CaANDSr)

2012 ◽  
Vol 26 (32) ◽  
pp. 1250199 ◽  
Author(s):  
M. HARMEL ◽  
H. KHACHAI ◽  
M. AMERI ◽  
R. KHENATA ◽  
N. BAKI ◽  
...  
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Theoretical Data ◽  
Full Potential ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Electronic And Optical Properties ◽  
Structure Density

Density functional theory (DFT) is performed to study the structural, electronic and optical properties of cubic fluoroperovskite AMF3( A = Cs ; M = Ca and Sr ) compounds. The calculations are based on the total-energy calculations within the full-potential linearized augmented plane wave (FP-LAPW) method. The exchange-correlation potential is treated by local density approximation (LDA) and generalized gradient approximation (GGA). The structural properties, including lattice constants, bulk modulus and their pressure derivatives are in very good agreement with the available experimental and theoretical data. The calculations of the electronic band structure, density of states and charge density reveal that compounds are both ionic insulators. The optical properties (namely: the real and the imaginary parts of the dielectric function ε(ω), the refractive index n(ω) and the extinction coefficient k(ω)) were calculated for radiation up to 40.0 eV.

Investigation of the structural, electronic, elastic and thermodynamic properties of Curium Monopnictides: An ab initio study

2017 ◽  
Vol 31 (30) ◽  
pp. 1750226 ◽  
Author(s):  
H. Baaziz ◽  
Dj. Guendouz ◽  
Z. Charifi ◽  
S. Akbudak ◽  
G. Uğur ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
Density Functional ◽  
Local Density ◽  
Structural Parameters ◽  
Structural Phase ◽  
Full Potential ◽  
Generalized Gradient ◽  
Metallic Behavior ◽  
Spin Polarized

The structural, electronic, elastic and thermodynamic properties of Curium Monopnictides CmX (X = N, P, As, Sb and Bi) are investigated using first-principles calculations based on the density functional theory (DFT) and full potential linearized augmented plane wave (FP-LAPW) method under ambient condition and high pressure. The exchange-correlation term is treated using two approximations spin-polarized local density approximation (LSDA) and spin-polarized generalized gradient approximation generalized (GGA). The structural parameters such as the equilibrium lattice parameters, bulk modulus and the total energies are calculated in two phases: namely NaCl (B1) and CsCl (B2). The obtained results are compared with the previous theoretical and experimental results. A structural phase transition from B1 phase to B2 phase for Curium pnictides has been obtained. The highest transition pressure is 122 GPa for CmN and the lowest one is 10.0 GPa for CmBi compound. The electronic properties show that these materials exhibit half-metallic behavior in both phases. The magnetic moment is found to be around 7.0 [Formula: see text]B. The mechanical properties of CmX (X = N, P, As, Sb and Bi) are predicted from the calculated elastic constants. Our calculated results are in good agreement with the theoretical results in literature. The effect of pressure and temperature on the thermodynamic properties like the cell volume, bulk modulus and the specific heats C[Formula: see text] and C[Formula: see text], the entropy [Formula: see text] and the Grüneisen parameter [Formula: see text] have been foreseen at expanded pressure and temperature ranges.

scholarly journals Extreme pressure conditions of bas based materials: Detailed study of structural changes, band gap engineering, elastic constants and mechanical properties

2019 ◽  
Vol 13 (4) ◽  
pp. 401-410
Author(s):  
Dejan Zagorac ◽  
Jelena Zagorac ◽  
Klaus Doll ◽  
Maria Cebela ◽  
Branko Matovic
Keyword(s):  
Mechanical Properties ◽  
Band Gap ◽  
Elastic Constants ◽  
Density Functional ◽  
Structural Changes ◽  
High Pressures ◽  
Local Density ◽  
Structure Property ◽  
Generalized Gradient ◽  
Band Gap Engineering

A Density Functional Theory (DFT) study has been performed in order to investigate behaviour of barium sulfide (BaS) at high pressures, and relationship between computed properties, in great detail. Novel predicted and previously synthesized BaS modifications have been calculated using Local Density Approximations (LDA) and Generalized Gradient Approximation (GGA) functionals. In particular, a detailed investigation of structural changes and its corresponding volume effect up to 100GPa, with gradual pressure increase, has been performed from the first principles. Band gap engineering of the experimentally observed BaS phases at high pressures has been simulated and structure-property relationship is investigated. For each of the predicted and experimentally observed BaS structures, elastic constants and mechanical properties under compression have been investigated (e.g. ductility/brittleness, hardness, anisotropy). This study offers a new perspective of barium sulphide as a high pressure material with application in ceramics, optical and electrical technologies.

First-Principles Study of Structural, Electronic, Optical and Elastic Properties of Cadmium Based Fluoro-Perovskite MCdF3 (M= Rb, Tl)

2019 ◽  
Vol 297 ◽  
pp. 173-186 ◽  
Author(s):  
Abderrahmane Cheriet ◽  
Brahim Lagoun ◽  
Mohamed Halit ◽  
Mourad Zaabat ◽  
Chadli Abdelhakim ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Density Functional ◽  
Elastic Anisotropy ◽  
Local Density ◽  
Poisson Ratio ◽  
Exchange Potential ◽  
Full Potential ◽  
Generalized Gradient ◽  
Pressure Derivative ◽  
Conduction Bands

This paper presents a theoretical study using the full potential linearized augmented plane wave approach (FP-LAPW) based on the density functional theory (DFT) to predict the structural and electronic properties of RbCdF3 and TlCdF3 compounds. The exchange-correlation potential is treated by the local density approximation (LDA), generalized gradient approximation (GGA) and modified Beck-Johnson exchange potential (mBJ). The calculated structural properties such as the equilibrium lattice parameter, the bulk modulus and its pressure derivative are in good agreement with the available data. The obtained results for the band structure and the density of states (DOS) show that the RbCdF3 (TlCdF3) compound have an indirect band gap of 6.77 and 3.07 eV (5.70 and 3.66 eV) with TB-mBJ and WC method respectively. From the electronic transition from valence conduction bands to conduction bands the optical properties were calculated. The elastic constants were calculated using the energy deformation relationship, from these constants the other mechanical properties such as bulk modulus, shear modulus, Young modulus and Poisson ratio were calculate and comment. Lastly, the elastic anisotropy was discussed.

Electronic structure, optical and thermodynamic properties of ternary hydrides MBeH3 (M = Li, Na, and K)

2016 ◽  
Vol 94 (9) ◽  
pp. 865-876 ◽  
Author(s):  
Dj Guendouz ◽  
Z. Charifi ◽  
H. Baaziz ◽  
T. Ghellab ◽  
N. Arikan ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Thermodynamic Properties ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Debye Model ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Electron Charge Density ◽  
Principal Aspect

Electronic band structure, optical and thermodynamic properties of ternary hydrides MBeH3 (M = Li, Na, and K) were studied using ab initio density functional theory (DFT). The effect of the adopted approximation to the exchange-correlation functional of the DFT is explicitly investigated by considering four different expressions of two different classes (local-density approximation and generalized-gradient approximation). The calculated magnitude of B classifies MBeH3 (M = Li, Na, and K) as easily compressible materials. The bonding interaction in these compounds is quite complicated. The interaction between M and BeH6 is ionic and that between Be and H comprises both ionic and covalent characters. The electronic structure of the complex hydride was investigated by calculating the partial and total densities of states, and electron charge density distribution. Large gaps in the density of states appear at the Fermi energy of LiBeH3, NaBeH3, and KBeH3 indicating that these classes of hydrides are insulators. Optical properties, including the dielectric function, reflectivity, and absorption coefficient, each as a function of photon energy, are calculated and show an optical anisotropy for LiBeH3 and KBeH3. Through the quasi-harmonic Debye model, in which the phononic effects are considered, temperature dependence of volume V(T), bulk modulus B(T), and thermal expansion coefficient α(T), constant-volume and constant-pressure specific heat (Cv and Cp) and Debye temperature ΘD, the entropy S, and the Grüneisen parameter γ were calculated at wide pressure and temperature ranges. The principal aspect of the obtained results is the close similarity of MBeH3 (M = Li, Na, and K) compounds.

Effect of Pressure on Structural, Electronic and Elastic Properties of Cubic (Pm3m) SnTiO3 Using First Principle Calculation

2012 ◽  
Vol 501 ◽  
pp. 342-346 ◽  
Author(s):  
M.F.M. Taib ◽  
M.K. Yaakob ◽  
Amreesh Chandra ◽  
Abdul Kariem Mohd Arof ◽  
M.Z.A. Yahya
Keyword(s):  
Band Gap ◽  
Elastic Properties ◽  
Elastic Constants ◽  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Perovskite Oxide ◽  
First Principles Calculation ◽  
Cubic Phase ◽  
Electronic Band

The electronic band structure, density of state and elastic properties of lead-free perovskite oxide SnTiO3 (ST) were investigated by employing first principles calculation using the Density Functional Theory (DFT) within local density approximation (LDA). The energy band gap was calculated from the separation between the Ti 3d (conduction band) and the maximum of O 2p (valence band). This gives an indirect band gap of 2.36 eV. The elastic constants and their pressure dependence were calculated up to 30 GPa and the independent elastic constants (C11, C12, and C44), bulk modules, B were obtained and analyzed. The results showed that SnTiO3 have a mechanical stability in cubic phase (Pm3m).

First Principles Study on Structural and Electronic Properties of PZT and PSnZT Using Density Functional Theory

2016 ◽  
Vol 846 ◽  
pp. 734-739 ◽  
Author(s):  
N.H. Hussin ◽  
Mohamad Fariz Mohamad Taib ◽  
F.W. Badrudin ◽  
N.A. Johari ◽  
Nunshaimah Salleh ◽  
...  
Keyword(s):  
Density Functional ◽  
Electronic Band Structure ◽  
Local Density ◽  
Geometry Optimization ◽  
Lone Pair ◽  
Lattice Parameter ◽  
Density Of State ◽  
Generalized Gradient ◽  
Electronic Band ◽  
Indirect Band Gap

The geometry optimization of the tetragonal supercell 1x1x2 (P4mm, 99 space group) of PZT and PSnZT were calculated using different exchange correlation functional such as Local Density Approximate (LDA-CAPZ) and Generalized Gradient Approximation (GGA-PBE & GGA-PBEsol).The calculation using functional GGA-PBEsol exhibits the most accurate values of lattice parameter and volume of structure relative to the experiment results with typical error of approximately 1% underestimate (only for PZT-as reference materials). The electronic band structure and density of state (DOS) were also studied in order to understand the electron density and hybrization between cation and anion in the compound. The density of state studies indicated existing of hybridizations among anion O 2p, cation Pb 6s/Sn 5s (special lone pair) and the Ti 3d/Zr 4d states of PZT and PSnZT compound. An indirect band gap was respectively obtained for both cubic PZT and PSnZT at the F-G and Q-G point with 3.154 eV and 2.571 eV.

Half-metallicity and optoelectronic properties of V-doped zincblende ZnS and CdS alloys

2016 ◽  
Vol 30 (08) ◽  
pp. 1650034 ◽  
Author(s):  
Mohammed El Amine Monir ◽  
H. Baltache ◽  
R. Khenata ◽  
G. Murtaza ◽  
R. Ahmed ◽  
...  
Keyword(s):  
Magnetic Moment ◽  
Density Functional ◽  
Spin Exchange ◽  
Electronic Band Structure ◽  
Magnetic Behavior ◽  
Full Potential ◽  
Generalized Gradient ◽  
Half Metallicity ◽  
Electronic Band ◽  
Half Metallic

In this paper, spin-polarized density functional calculations on the structural, electronic, optical and magnetic properties of the zincblende structure of the [Formula: see text] and [Formula: see text] alloys at [Formula: see text] in the ferromagnetic (FM) ordering has been investigated. The study is accomplished using the full-potential (FP) linearized augmented plane wave plus local orbital (LAPW[Formula: see text]lo) self-consistent scheme of calculations. To incorporate the exchange correlation component in the total energy calculations of the crystal, Perdew–Burke and Ernzerhof (PBE) parameterization for the generalized gradient approximation (GGA) and GGA[Formula: see text]U are employed. Basically, for both alloys, to address their structural properties, we calculated their equilibrium lattice constants, bulk moduli as well as pressure derivatives. In general, from the analysis of the obtained electronic band structure of these alloys, the half-metallic nature of [Formula: see text] and nearly half-metallic nature of the [Formula: see text] alloy are demonstrated. The plotted density of states (DOS) curves project spin-exchange splitting energy [Formula: see text] and [Formula: see text] as generated by V-3d states. It has been clearly evident that the effective potential results for the spin-down case are more striking than for the spin-up case. In order to describe the magnetic behavior of these alloys, the exchange constants [Formula: see text] (valence band) and [Formula: see text] (conduction band) as well as the magnetic moment values are estimated. The calculated results of the magnetic moment show that the main source in the reduction of the local magnetic moment of V in the alloys in comparison with its free value is a [Formula: see text]–[Formula: see text] orbital hybridization and partial transfer to nonmagnetic sites of (Zn, S) and (Cd, S) in [Formula: see text] and [Formula: see text] alloys. In addition, a study concerning optical properties, such as the refractive index, reflectivity and absorption coefficients is performed to determine their potential for optical and optoelectronic devices.

ELECTRONIC AND OPTICAL PROPERTIES OF BaO, BaS, BaSe, BaTe AND BaPo COMPOUNDS UNDER HYDROSTATIC PRESSURE

2009 ◽  
Vol 23 (26) ◽  
pp. 3065-3079 ◽  
Author(s):  
S. DRABLIA ◽  
H. MERADJI ◽  
S. GHEMID ◽  
N. BOUKHRIS ◽  
B. BOUHAFS ◽  
...  
Keyword(s):  
Optical Properties ◽  
Dielectric Function ◽  
Imaginary Part ◽  
Density Functional ◽  
Energy Gap ◽  
Electronic Band Structure ◽  
Local Density ◽  
Full Potential ◽  
Electronic Band ◽  
Electronic And Optical Properties

We have performed first-principle full-potential (linear) augmented plane wave plus local orbital calculations (FP-L/APW + l0) with density functional theory (DFT) in local density approximation (LDA) and generalized gradient approximation (GGA), with the aim to determine and predict the electronic and optical properties of rocksalt BaO , BaS , BaSe , BaTe and BaPo compounds. First we present the main features of the electronic properties of these compounds, where the electronic band structure shows that the fundamental energy gap is indirect (Γ–X) for all compounds except for BaO which is direct (X–X). The different interband transitions have been determined from the imaginary part of the dielectric function. The real and imaginary parts of the dielectric function and the reflectivity are calculated. We have presented the assignment of the different optical transitions existing in these compounds from the imaginary part of the dielectric function spectra with respect to their correspondence in the electronic band. We have also calculated the pressure and volume dependence of the optical properties for these compounds.

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