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

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.

2021 ◽  
Vol 1028 ◽  
pp. 199-203
Author(s):  
Fiqhri Heda Murdaka ◽  
Edi Suprayoga ◽  
Abdul Muizz Pradipto ◽  
Kohji Nakamura ◽  
Agustinus Agung Nugroho

We report the estimation of muon sites inside Mn3Sn using density functional theory based on the full-potential linearized augmented plane wave (FLAPW) calculation. Our calculation shows that the Perdew–Burke–Ernzerhof (PBE) Generalized-Gradient Approximation (GGA) functional is closer to the experimental structure compared to the von Barth-Hedin Local Density Approximation (LDA)-optimized geometry. The PBE GGA is therefore subsequently used in FLAPW post-calculation for the electrostatic potential calculation to find the local minima position as a guiding strategy for estimating the muon site. Our result reveals at least two muon sites of which one is placed at the center between two Mn-Sn triangular layers (A site) and the other at the trigonal prismatic site of Sn atom (B site). The total energy of Mn3Sn system in the presence of muon at A site or B site are compared and we find that A site is a more favorable site for muon to stop.


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.


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.


2019 ◽  
Vol 9 (3) ◽  
pp. 199-211
Author(s):  
Mohammed Ait Haddouch ◽  
Youssef Tamraoui ◽  
Fatima-Ezzahra Mirinioui ◽  
Youssef Aharbil ◽  
Hicham Labrim ◽  
...  

A series of strontium calcium tungstates Sr1-xCaxWO4 powders with (x = 0; 0.25; 0.5; 0.75 and 1.0) were prepared by solid-state reaction method and analyzed by X-ray diffraction (XRD). All these compositions possess a tetragonal scheelite structure with I41/a space group. Raman active vibrational modes in the range from 20 to 1000 cm-1 of the series Sr1-xCaxWO4 with tetragonal structure exhibit 13 modes in arrangement with the Group theory analysis of structural Raman-active modes. The optical properties were investigated using the diffuse reflectance UV–visible absorbance spectrum. Based on Density Functional Theory (DFT) and using full Potential-linearized Augmented Plane Wave (FP-LAPW) method with the Local Density Approximation and the Generalized Gradient Approximation (GGA), implemented in the Wien2k package, we have investigated electronic and optical properties of all the compositions. The results indicate a decrease in the values of the optical direct bandgap (from 4.29 to 3.87 eV) with the increase of Ca into SrWO4 lattice, which is in good agreement with our experimental results.


2019 ◽  
Vol 297 ◽  
pp. 82-94
Author(s):  
Amira El Hassasna ◽  
Abderrachid Bechiri

In this work we investigated the structural, electronic and elastic properties of TlN, TlP, TlAs and TlSb compounds in the zinc-blende phase, the lattice parameter, bulk modulus, band structure, and elastic constants have been calculated by employing the full potential linearized augmented plane wave method based on density functional theory of the exchange-correlation potentials including local density approximation, PBE generalized gradient, and Wu-Cohen generalized gradient are used. Furthermore, the modified Backe-Johnson (mBJ) potential has been utilized for the calculation of the energy gap. The present results are compared with other available theoretical values obtained.


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.


2012 ◽  
Vol 624 ◽  
pp. 117-121 ◽  
Author(s):  
Fan Jun Zeng ◽  
Qing Lin Xia

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.


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.


1985 ◽  
Vol 63 ◽  
Author(s):  
Arthur J. Freeman ◽  
C. L. Fu ◽  
T. Oguchi

ABSTRACTAdvances in all-electron local density functional theory approaches to complex materials structure and properties made possible by the implementation of new computational/theoretical algorithms on supercomputers are exemplified in our full potential linearized augmented plane wave (FLAPW) method. In this total energy self-consistent approach, high numerical stability and precision (to 10 in the total energy) have been demonstrated in a study of the relaxation and reconstruction of transition metal surfaces. Here we demonstrate the predictive power of this method for describing the structural, magnetic and electronic properties of several systems (surfaces, overlayers, sandwiches, and superlattices).


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