scholarly journals Ab initio studies of structural, electronic, optical, elastic and thermal properties of CuGaTe-=SUB=-2-=/SUB=-

Author(s):  
Pravesh Singh ◽  
Sheetal Sharma ◽  
Sarita Kumari ◽  
Vibhav K Saraswat ◽  
D. Sharma ◽  
...  

We have performed ab initio calculations for the structural, electronic, optical, elastic and thermal properties of CuGaTe2. In this study, we used an accurate full potential linearized augmented plane wave (FP-LAPW) method to find the equilibrium structural parameters and to compute the full elastic tensors. We report electronic and optical properties with the recently developed density functional of Tran and Blaha. Furthermore, optical features such as dielectric functions, refractive indices, extinction coefficient, optical reflectivity, absorption coefficients, optical conductivities, were calculated for photon energies up to 30 eV. The thermodynamical properties such as Debye temperature, entropy and Gruneisen parameter, bulk modulus and hardness were calculated employing the quasi-harmonic Debye model at different temperatures (0-1000 K) and pressures (0-8 GPa) and the silent results were interpreted. Most of the investigated parameters are reported for the first time. DOI: 10.21883/FTP.2017.05.44433.8044

2021 ◽  
Author(s):  
Souheyla Gagui ◽  
Sebti Ghemid ◽  
Hocine Meradji ◽  
Beddiaf Zaidi ◽  
Bakhtiar Ul Haq ◽  
...  

Abstract The knowledge of the physical properties of a material is crucial to realize its practical technological applications.Here, a study related to phase stability, transition pressure, electronic, optical,and thermal propertiesof GaAs, GaN, as well as their mixed ternary alloys GaN0.25As0.75, GaN0.5As0.5, andGaN0.75As0.25 is presented. The study is performed by employing "full-potential linearized augmented-plane-wave plus local-orbital, (FP-L(APW+lo))approach framed within density functional theory (DFT)" and recognized within WIEN2k computational code. The results of the phase stability show that the GaNxAs1-x alloys are stable for all compositions in the zinc blendephase (B3),except for x=1,, whereas the structure corresponding to x=1 composition is found to be more stable inthe wurtzite (B4) phase. The physicalproperties of the more stable phases corresponding to each composition are explored. The pressure-induced phase transition is also investigatedcorresponding to each composition. The electronic and optical properties are investigated using the Tran-Blahamodified Becke-Johnson (mBJ) potential approach. To explore the thermal properties, the "quasi-harmonic Debye model" approach is employed. Our calculated results of the absorption coefficients and optical band gap show that these alloys could be appropriate candidates for applications in solar cell and optoelectronic devices.


2019 ◽  
Vol 33 (07) ◽  
pp. 1950045
Author(s):  
R. Mahdjoubi ◽  
Y. Megdoud ◽  
L. Tairi ◽  
H. Meradji ◽  
Z. Chouahda ◽  
...  

First-principles calculations of the structural, electronic, optical and thermal properties of chalcopyrite CuXTe2 (X[Formula: see text]=[Formula: see text]Al, Ga, In) have been performed within density functional theory using the full-potential linearized augmented plane wave (FP-LAPW) method, by employing for the exchange and correlation potential the approximations WC-GGA and mBJ-GGA. The effect of X cations replacement on the structural, electronic band structure, density of states and optical properties were highlighted and explained. Our results are in good agreement with the previous theoretical and experimental data. As far as we know, for the first time we find the effects of temperature and pressure on thermal parameters of CuAlTe2 and CuGaTe2 compounds. Thermal properties are very useful for optimizing crystal growth, and predict photovoltaic applications on extreme thermodynamic conditions.


2014 ◽  
Vol 1047 ◽  
pp. 61-64
Author(s):  
Veena Thakur ◽  
Gitanjali Pagare ◽  
Sunil S. Chouhan ◽  
Sankar P. Sanyal

The structural, electronic and elastic properties of nonmagnetic LuPd3compound, which crystallize in AuCu3-type structure, are studied using first principles density functional theory based on full potential linearized augmented plane wave (FP-LAPW) method. The calculations are carried out within the PBE-sol GGA for the exchange correlation potential. The ground states properties such as lattice parameter (ao), bulk modulus (B) and pressure derivative (B') have been obtained using optimization method. The elastic properties such as Young’s modulus (E), Poisson’s ratio (σ) and anisotropic ratio (A) and thermal are predicted for first time. The ductility of these compounds has been analyzed using Pugh criteria.


2018 ◽  
Vol 2 (1) ◽  

Structural, elastic and thermal properties of lanthanide monoantimonides LnSb (Ln = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) compounds have been studied theoretically using full potential linearized augmented plane wave plus local orbitals (FP-LAPW + lo) method within the density functional theory. The structural properties are investigated by using GGA-PBEsol scheme. We calculated bulk modulus, shear modulus, Young’s modulus, anisotropic ratio, Kleinman parameters, Poisson’s ratio, Lame’s co-efficient, sound velocities for shear and longitudinal waves, and Debye temperature. We also predict the Cauchy pressure and B/G ratio in order to explore the ductile and brittle behaviors of these compounds.Our results are in good agreement with available experimental and other theoretical data and also provide predictions where no experimental or theoretical results are available.


Author(s):  
Ekta Jain ◽  
Gitanjali Pagare ◽  
Sankar P. Sanyal

An ab-initio investigation on structural, electronic, optical, elastic and thermal properties of CuZr intermetallic compound using full-potential linearized augmented plane wave method in the support of density functional theory at ambient condition have been performed. We have employed the generalized gradient approximation of (PBE) to indulgence the exchange correlation potential by solving Kohn-Sham equations. Total energy of CuZr as a function of the unit cell volume has been calculated using full potential linearized augmented plane wave (FP-LAPW) method in B1, B2 and B3 crystal structure to obtain the ground state properties. The study of different phases regarding their enthalpy vs. pressure variation is also presented. Our calculated structural parameters (a0 = 3.268 Å, B = 119 GPa and B' = 4.95) of CuZr are consistent with both the available experimental (a0 = 3.262 Å) and previously presented theoretical data (a0 = 3.280 Å, B = 121 GPa) for B2-type (CsCl) crystal structure. The results obtained from density of states (DOS) and optical spectra shows that the present compound is metallic. The value of density of states at the Fermi level N (EF) is found to 3.89 states/eV which is determined due to the contribution of ‘d’ like states of Cu and Zr and ‘p’ like states of Zr atom. The second order elastic constants are comparatively studied and an excellent agreement is found with other theoretical data. The trend of calculated elastic constants i.e. C11 - C12 > 0, C11 > 0, C44 > 0, C11 + 2C12 > 0 shows the stability criteria for B2-type (CsCl) crystal structure at ambient pressure. The sound velocities for longitudinal and shear waves, Debye average velocity and Debye temperature have been successfully calculated as a first theoretical prediction.


2003 ◽  
Vol 793 ◽  
Author(s):  
Daniel I Bilc ◽  
S.D. Mahanti ◽  
M.G. Kanatzidis

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.


2018 ◽  
Vol 32 (11) ◽  
pp. 1850129 ◽  
Author(s):  
Shahram Yalameha ◽  
Aminollah Vaez

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.


Author(s):  
Deepika Shrivastava ◽  
Sankar P. Sanyal

The structural, electronic and elastic properties of CeTl with CsCl-type B2 structure have been investigated using full-potential linearized augmented plane wave (FP-LAPW) method based on density functional theory (DFT) within the generalized gradient approximation (GGA) for exchange and correlation potential. The ground state properties such as lattice constant, bulk modulus and pressure derivative of bulk modulus have been calculated which are in good agreement with available experimental data. The band structure and density of state depict that 4f electrons of Ce element have dominant character in electronic conduction and are responsible for metallic character of CeTl. The charge density plot reveals that the metallic as well as ionic bonding exist between Ce and Tl atoms. The calculated elastic constants indicate that CeTl is mechanically stable in cubic B2 phase and found to be ductile in nature.


Author(s):  
Mani Shugani ◽  
Mahendra Aynyas ◽  
Sankar P. Sanyal

We have performed First-principles density functional calculation by using full potential linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation (GGA) of B2- AlGd (Aluminum compound). The ground state properties along with electronic and elastic properties are studied. The energy ranges are given for bands which are crossing the Fermi level and explained whether the Fermi surface is formed by hole pocket or electron pocket. Bonding properties are analyzed by charge density plot. By B/GH ratio the brittleness of the material is determined.


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