The study of structural, elastic, electronic and optical properties of CsYx I(1 − x)(Y = F, Cl, Br) using density functional theory (original) (raw)
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Structural, elastic, electronic, and optical properties of cubic perovskite CsCaCl3 are calculated using the full-potential linearized augmented plane wave method in the density functional theory. The exchange-correlation potential is evaluated using the local density approximation and generalized gradient approximation. Further, the modi ed BeckeJohnson potential is also applied for studying the electronic and optical properties. The calculated structural properties such as equilibrium lattice constant, the bulk modulus and its pressure derivative are in good agreement with the available data. The elastic properties such as elastic constants, anisotropy factor, shear modulus, Young's modulus and Poisson's ratio are calculated. The calculations of electronic band structure, density of states and charge density show that this compound has an indirect energy band gap (M) with a mixed ionic and covalent bonding. Calculations of the optical spectra such as the real and imaginary parts of dielectric function, optical re ectivity, absorption coe cient, optical conductivity, refractive index, extinction coe cient and electron energy loss are performed for the energy range of 030 eV. Most of the studied properties are reported for the rst time for CsCaCl3.
Elastic Properties of (CsCN)x(CsX)1-x, Mixed Crystal
Asian Journal of Applied Science and Technology (AJAST) , 2024
The TOEC's elastic characteristics of mixed alkali cyanide-alkali halide crystal (CsCN)x(CsX)1-x (X= Cl) for x=0, 0.28, 0.59, and 0.96 at various temperatures have been examined using an Extended three-body force shell model (ETSM). The effect of coupling between the cyanide molecules' rotational and translational motion is included in this model. Finite elasticity, in which elastic stress is non-linear with elastic strain, is the responsibility of the TOECs. In some crystallographic planes, the elastic shear behaviour is asymmetric with regard to shear displacements. The knowledge of ion-core repulsive interactions; which vary with the interatomic separation; is related to the third order elastic constants.
Advances in material science and engineering, 2022
E cient materials with good optoelectronic properties are required for the good performance of photovoltaic devices. In this work, we present ndings of a theoretical investigation of the structural, electronic, elastic, mechanical, and optical properties of K 2 CuX (X As, Sb) ternary compounds. e computations were carried out by using the density functional theory (DFT) formalism as implemented in the quantum espresso (QE) software package. e calculated lattice constants of 19.1414 a.u (K 2 CuAs) and 20.0041 a.u (K 2 CuSb) are in agreement with the experimental results from the literature. e materials under study were found to have bandgaps of 1.050 eV (K 2 CuAs) and 1.129 eV (K 2 CuSb). e valence band was majorly formed by Cu-3d, As-2p, and Cu-4s states while the conduction band was majorly dominated by Cu-5p in K 2 CuAs, whereas in K 2 CuSb, the valence band was mainly formed by Cu-3d, Cu-4s, and Sb-3p states while the conduction band was majorly formed by Sb-3p and Cu-5p states. e investigated materials were found to be mechanically stable at zero pressure, ductile, and ionic. e optical absorption coe cient curves were found to cover the ultraviolet to visible (UV-Vis) regions, thus making K 2 CuAs and K 2 CuSb good UV-Vis absorbers hence their suitability for photovoltaic applications.
Understanding the physical properties of a material is crucial to know its applicability for practical applications. In this study, we investigate the phase stability, elastic, electronic, thermal, and optical properties of the ternary alloying of the scandium and yttrium nitrides (Sc1 − xYxN) for different compositions. To do so, we apply a “density functional theory (DFT)” based scheme of calculations named as “full potential (FP) linearized (L) augmented plane wave plus local orbitals (APW + lo) method" realized in the WIEN2k computational package. At first, the phase stability of the investigated compositions of the mentioned alloy is determined. The analysis of our calculations shows that Sc1 − xYxN alloy is stable in rock salt crystal structure for all investigated compositions. Next to that, the elastic properties of the rock-salt phase of the studied ternary alloy Sc1 − xYxN at all above said compositions were done at the level of “Wu-Cohen generalized gradient approxim...