STRUCTURAL, ELECTRONIC, THERMODYNAMIC AND THERMAL PROPERTIES OF ZINC-BLENDE InP, InAs AND THEIR InAsx P1-x TERNARY ALLOYS VIA FIRST PRINCIPLES CALCULATIONS

2013 ◽  
Vol 27 (27) ◽  
pp. 1350166 ◽  
Author(s):  
O. NEMIRI ◽  
S. GHEMID ◽  
Z. CHOUAHDA ◽  
H. MERADJI ◽  
F. EL HAJ HASSAN
Keyword(s):  
Thermal Properties ◽  
Bulk Modulus ◽  
Band Gap ◽  
Lattice Constant ◽  
First Principles ◽  
Density Functional ◽  
Experimental Studies ◽  
Ternary Alloys ◽  
Full Potential ◽  
First Principles Calculations

First-principles calculations are performed to study the structural, electronic, thermodynamic and thermal properties of the InP and InAs bulk materials and InAs x P 1-x ternary alloys using the full potential-linearized augmented plane wave method (FP-LAPW) within the density functional theory (DFT). The dependence of the lattice constant, bulk modulus, band gap, Debye temperature, heat capacity and mixing entropy on the composition x was analyzed. The lattice constant for InAs x P 1-x alloys exhibits a marginal deviation from the Vegard's law. A large deviation of the bulk modulus from linear concentration dependence (LCD) was observed for our alloys. We found that the composition dependence of the energy band gap is almost linear by using the mBJ and EV-GGA approximations. The microscopic origins of the gap bowing were explained and detailed by using the approach of Zunger and co-workers. Furthermore, the calculated phase diagram shows a miscibility gap for these alloys with a high critical temperature. Thermal effects on some macroscopic properties of InAs x P 1-x alloys are predicted using the quasi-harmonic Debye model, in which the phononic effects are considered. This is the first quantitative theoretical prediction of the thermal properties of the InAs x P 1-x alloys, and we still expect the confirmation of experimental studies.

FIRST PRINCIPLES CALCULATIONS OF STRUCTURAL, ELECTRONIC, THERMODYNAMIC AND THERMAL PROPERTIES OF BaxSr1-xTe TERNARY ALLOYS

2014 ◽  
Vol 28 (04) ◽  
pp. 1450041
Author(s):  
S. CHELLI ◽  
H. MERADJI ◽  
S. AMARA KORBA ◽  
S. GHEMID ◽  
F. EL HAJ HASSAN
Keyword(s):  
Thermal Properties ◽  
Bulk Modulus ◽  
Band Gap ◽  
Lattice Constant ◽  
Density Functional ◽  
Enthalpy Of Mixing ◽  
Mixed Crystals ◽  
Ternary Alloys ◽  
Full Potential ◽  
Generalized Gradient

The structural, electronic thermodynamic and thermal properties of Ba x Sr 1-x Te ternary mixed crystals have been studied using the ab initio full-potential linearized augmented plane wave (FP-LAPW) method within density functional theory (DFT). In this approach, the Perdew–Burke–Ernzerhof-generalized gradient approximation (PBE-GGA) was used for the exchange-correlation potential. Moreover, the recently proposed modified Becke Johnson (mBJ) potential approximation, which successfully corrects the band-gap problem was also used for band structure calculations. The ground-state properties are determined for the cubic bulk materials BaTe , SrTe and their mixed crystals at various concentrations (x = 0.25, 0.5 and 0.75). The effect of composition on lattice constant, bulk modulus and band gap was analyzed. Deviation of the lattice constant from Vegard's law and the bulk modulus from linear concentration dependence (LCD) were observed for the ternary Ba x Sr 1-x Te alloys. The microscopic origins of the gap bowing were explained by using the approach of Zunger and co-workers. On the other hand, the thermodynamic stability of these alloys was investigated by calculating the excess enthalpy of mixing, ΔHm as well as the phase diagram. It was shown that these alloys are stable at high temperature. Thermal effects on some macroscopic properties of Ba x Sr 1-x Te alloys were investigated using the quasi-harmonic Debye model, in which the phononic effects are considered.

First-principles calculations of structural, electronic and thermal properties of Zn1−x MgxS ternary alloys

Open Physics ◽  
2014 ◽  
Vol 12 (1) ◽  
Author(s):  
Samia Lamraoui ◽  
Rachid Bensalem ◽  
Khadidja Hacini ◽  
Hocine Meradji ◽  
Sebti Ghemid ◽  
...  
Keyword(s):  
Thermal Properties ◽  
Density Functional ◽  
Small Deviation ◽  
Experimental Studies ◽  
Theoretical Data ◽  
Debye Model ◽  
Ternary Alloys ◽  
Full Potential ◽  
Generalized Gradient ◽  
Vegard’S Law

AbstractStructural, electronic and thermal properties of Zn1−x MgxS ternary alloys are studied by using the full potential-linearized augmented plane wave method (FP-LAPW) within the density functional theory (DFT). The Wu-Cohen generalized gradient approximation (WC-GGA) is used in this approach for the exchangecorrelation potential. Moreover, the modified Becke-Johnson approximation (mBJ) is adopted for band structure calculations. The dependence of the lattice constant, bulk modulus and band gap on the composition x showed that the first exhibits a small deviation from the Vegard’s law, whereas, a marginal deviation of the second from linear concentration dependence (LCD). The bowing of the fundamental gap versus composition predicted by our calculations agrees well with the available theoretical data. The microscopic origins of the gap bowing are explained by using the approach of Zunger and co-workers. Thermal effects on some macroscopic properties of Zn1−x MgxS alloys are also investigated using the quasi-harmonic Debye model, in which the phononic effects are considered. As, this is the first quantitative theoretical prediction of the thermal properties of Zn1−x MgxS alloys, no other calculated results and furthermore no experimental studies are available for comparison.

First-principles studies on electronic structures and optical properties of two-dimensional Sn1−xTi(Zr)xS2 alloys

2018 ◽  
Vol 32 (07) ◽  
pp. 1850092 ◽  
Author(s):  
Dandan Li ◽  
Juan Du ◽  
Qian Zhang ◽  
Congxin Xia ◽  
Shuyi Wei
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
First Principles ◽  
Electronic Structures ◽  
Threshold Energy ◽  
Ternary Alloys ◽  
Two Dimensional ◽  
First Principles Calculations ◽  
Experimental Conditions ◽  
Part Formula

Through first-principles calculations we study the electronic structures and optical properties of two-dimensional (2D) Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys. The results indicate that the band gap value of Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys is decreased continuously when Ti(Zr) concentration is increased, which is very beneficial to optoelectronic devices applications. Moreover, the static dielectric constant is increased when the Ti(Zr) concentration is increased in the 2D Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys. In addition, we also calculate the imaginary part [Formula: see text] dispersion of Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 alloys along the plane with different Ti(Zr) concentrations. The threshold energy values decrease with increasing Ti(Zr) concentrations in the Sn[Formula: see text]Ti(Zr)[Formula: see text]S2 ternary alloys. Moreover, the calculations of formation energy also indicate that these 2D alloys can be fabricated under some experimental conditions. These results suggest that Ti(Zr) substituting Sn atom is an efficient way to tune the band gap and optical properties of 2D SnS2 nanosheets.

First-principles investigation of the structural, elastic, electronic, and optical properties of semiconducting AgBr1–xIx (0 ≤ x ≤ 1) ternary alloys in rock-salt and zinc blende structures

2020 ◽  
Vol 98 (9) ◽  
pp. 834-848
Author(s):  
H. Rekab-Djabri ◽  
Mohamed Drief ◽  
Manal M. Abdus Salam ◽  
Salah Daoud ◽  
F. El Haj Hassan ◽  
...  
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Rock Salt ◽  
Density Functional ◽  
Local Density ◽  
Ternary Alloys ◽  
Full Potential ◽  
Zinc Blende ◽  
Lmto Method ◽  
Direct Band

In this work, first principle calculations of the structural, electronic, elastic, and optical properties of novel AgBr1–xIx ternary alloys in rock-salt (B1) and zinc-blende (B3) structures are presented. The calculations were performed using the full-potential linear muffin-tin orbital (FP-LMTO) method within the framework of the density functional theory (DFT). The exchange and correlation potentials were treated according to the local density approximation (LDA). The lattice constants for the B1 and B3 phases versus iodide concentration (x) were found to deviate slightly from the linear relationship of Vegard’s law. The calculated electronic properties showed that AgBr1–xIx alloys in the B3 structure have a direct band gap (Γ – Γ) for all concentrations of x, which means that they can be used in long-wavelength optoelectronic applications, while in the B1 structure they have an indirect (Γ – R) band gap. The elastic constants Cij, shear modulus G, Young’s modulus E, Poisson’s ratio ν, index of ductility B/G, sound velocities vt, vl, and vm, and Debye temperature θD were also reported and analyzed. By incorporating the basic optical properties, we discussed the dielectric function, refractive index, optical reflectivity, absorption coefficient, and optical conductivity in terms of incident photon energy up to 13.5 eV. The present results were found to be in good agreement with the available experimental and other theoretical results.

First-Principles Calculations of Elastic Properties of HoBi and ErBi

2013 ◽  
Vol 664 ◽  
pp. 672-676
Author(s):  
De Ming Han ◽  
Gang Zhang ◽  
Li Hui Zhao
Keyword(s):  
Shear Modulus ◽  
Physical Properties ◽  
Bulk Modulus ◽  
Elastic Properties ◽  
Lattice Constant ◽  
Elastic Constants ◽  
First Principles ◽  
Energy Band ◽  
First Principles Calculations ◽  
Future Work

We present first-principles investigations on the elastic properties of XBi (X=Ho, Er) compounds. Basic physical properties, such as lattice constant, elastic constants (Cij), isotropic shear modulus (G), bulk modulus (B), Young’s modulus (Y), Poisson’s ratio (υ), and Anisotropy factor (A) are calculated. The calculated energy band structures show that the two compounds possess semi-metallic character. We hope that these results would be useful for future work on two compounds.

scholarly journals Theoretical Investigations of Structural Phase Transitions and Magnetic, Electronic and Thermal Properties of DyNi: Under High Pressures and Temperatures

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Pooja Rana ◽  
U. P. Verma
Keyword(s):  
Thermal Properties ◽  
Rare Earth ◽  
Bulk Modulus ◽  
Density Functional ◽  
High Pressures ◽  
Magnetic Moments ◽  
Structural Phase ◽  
Rare Earth Ions ◽  
Full Potential ◽  
Electronic Band

Present work is influenced by the requirement of investigation of rare earth intermetallics due to the nonavailability of theoretical details and least information from experimental results. An attempt has been made to analyse the structural, electronic, magnetic and thermal properties of DyNi using full potential linear augmented plane wave method based on density functional theory. DyNi differs from other members of lanthanides nickelates as in ground state it crystallizes in FeB phase rather than orthorhombic CrB structure. The equilibrium lattice constant, bulk modulus, and pressure derivative of bulk modulus are presented in four polymorphs (FeB, CrB, CsCl and NaCl) of DyNi. At equilibrium the cell volume of DyNi for FeB structure has been calculated as 1098.16 Bohr3 which is comparable well with the experimental value 1074.75 Bohr3. The electronic band structure has been presented for FeB phase. The results for thermal properties, namely, thermal expansion coefficient, Gruneisen parameter, specific heat and Debye temperature at higher pressure and temperatures have been reported. The magnetic moments at equilibrium lattice constants have also been tabulated as the rare earth ions associated with large magnetic moments increase their utility in industrial field for the fabrication of electronic devices due to their magnetocaloric effect used in magnetic refrigeration.

scholarly journals First-principles study on electronic, optic, elastic, dynamic and thermodynamic properties of RbH compound

2015 ◽  
Vol 6 ◽  
pp. A6 ◽  
Author(s):  
Sinem Erden Gulebaglan ◽  
Emel Kilit Dogan ◽  
Mehmet Nurullah Secuk ◽  
Murat Aycibin ◽  
Bahattin Erdinc ◽  
...  
Keyword(s):  
Thermodynamic Properties ◽  
Band Gap ◽  
Lattice Constant ◽  
First Principles ◽  
Density Functional ◽  
Temperature Dependent ◽  
Functional Theory ◽  
Salt Structure ◽  
Elastic Lattice ◽  
Good Agreement

We performed first-principles calculations to obtain the electronic, optical, elastic, lattice-dynamical and thermodynamic properties of RbH compound with rock salt structure. The ground-state properties, i.e., the lattice constant and the band gap were investigated using a plane wave pseudopotential method within density functional theory. The calculated lattice constant, bulk modulus, energy band gap and elastic constants are reported and compared with previous theoretical and experimental results. Our calculated results and the previous results which are obtained from literature are in a good agreement. Moreover, real and imaginary parts of complex dielectric function, reflectivity spectrum, absorption, extinction coefficient and loss function as a function of photon energy and refractive index with respect to photon wavelength were calculated. In addition, temperature dependent thermodynamic properties such as Helmholtz free energy, internal energy, entropy and specific heat have been studied.

scholarly journals Theoretical Prediction of Lanthanum Composition Effects on Structural, Electronic and Thermal Properties of LaxSc1-XN Alloys.

2021 ◽  
Author(s):  
Amira EL-HASSASNA ◽  
CHAOUCHE Yassine ◽  
Louafi Ahd
Keyword(s):  
Thermal Properties ◽  
Density Functional ◽  
Correlation Energy ◽  
Small Deviation ◽  
Debye Model ◽  
Ternary Alloys ◽  
Full Potential ◽  
Generalized Gradient ◽  
Salt Structure ◽  
Binary Compounds

Abstract In this paper we have study the structural, electronic and thermal properties of LaxSc1−xN ternary alloys in rock-salt structure by the use of full potential linearized augmented plane wave (FP-LAPW) method based to the density functional theory (DFT). For calculate the exchange-correlation energy and potential we are used both the Wu-Cohen generalized gradient (WC-GGA) approximation and the modified Becke-Johnson(mBJ).We investigated the fact of composition on lattice parameters, bulk modulus and band gap. The variation of calculated lattice constant with lanthanum composition is almost linear and shows a small deviation of the obtained results from Vegard’s law. The semiconductor nature of binary compounds ScN and LaN was confirmed. Our finding indicates that the LaxSc1−xN alloys are semiconductor with x = 0.5 and 0.75, on the contrary for x = 0.25 has a metallic nature. Lastly, the effect of thermal macroscopic properties is also investigated employing the quasi-harmonic Debye model in which the lattice vibrations are taken into account. We have found a good accord between our results and the experimental data and previous theoretical results available in the literature for the binary compounds which can be a support for the ternary alloys in the future.

scholarly journals Structural and electronic properties of the spinel Li4Ti5O12

2019 ◽  
Vol 20 (46) ◽  
pp. 7-12 ◽  
Author(s):  
Sarantuya Lkhagvajav ◽  
Namsrai Tsogbadrakh ◽  
Enkhjargal Enkhbayar ◽  
Sevjidsuren Galsan ◽  
Pagvajav Altantsog
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Experimental Studies ◽  
First Principles Calculations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Structural And Electronic Properties ◽  
Hubbard U ◽  
Uv Visible

In this study, the structure and electronic properties of the spinel compound Li4Ti5O12 (LTO) are investigated both theoretical and experimental methods. The experimental studies of structural and electronic properties were performed by X-ray diffraction and UV-visible spectroscopy. The first principles calculations allowed to establish the relationship between the structure and electronic properties. The spinel type structure of LTO is refined by the Rietveld analysis using the X-ray diffraction (XRD). The band gap of LTO was determined to be 3.55 eV using the UV-visible absorption spectra. The Density functional theory (DFT) augmented without and with the Hubbard U correction (GGA and GGA +U+J0) is used to elucidate the electronic structure of LTO. We have performed systematic studies of the first principles calculations based on the GGA and GGA+U for the crystal structure and electronic properties of spinel LTO. We propose that a Hubbard U correction improves the DFT results.

First-principles calculations to investigate structural, electronic and optical properties of (ZnSe)n/(ZnTe)n superlattices

2020 ◽  
Author(s):  
Messaoud Caid
Keyword(s):  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Correlation Energy ◽  
Local Density ◽  
Full Potential ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Lmto Method ◽  
Binary Compounds

An investigation into the structural, electronic and optical properties of superlattices(SLs) (ZnSe)n/(ZnTe)n was conducted using first principles calculations based on density functional theory (DFT). The total energies were calculated within the full-potential linear muffin-tin orbital (FP-LMTO) method augmented by a plane-wave basis (PLW), implemented in LmtART 7.0 code. The effects of the approximations to the exchange-correlation energy were treated by the local density approximation (LDA). The ground state properties of (ZnSe)n/(ZnTe)n binary compounds are determined and compared with the available data. It is found that the superlattice (n-n: 1-1, 2-2 and 3-3) band gaps vary depending on the layers used. The optical constants, including the dielectric function ε(w), the refractive index n(w) and the reflectivity R(w), are calculated for radiation energies up to 35eV.

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