ORCID Profile
0000-0003-4957-2192
Current Organisation
Chittagong University of Engineering and Technology
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Publisher: World Scientific Pub Co Pte Lt
Date: 23-06-2016
DOI: 10.1142/S0217979216500892
Abstract: The elastic, electronic, and optical properties of [Formula: see text] [Formula: see text], [Formula: see text] are investigated for the first time using the density-functional formalism. The optimized crystal structure is obtained and the lattice parameters are compared with available experimental data. Different elastic moduli are calculated. The Born criteria for mechanical stability are found to be fulfilled from the estimated values of the elastic moduli, [Formula: see text]. The band structure and the electronic energy density of states (EDOS) are also determined. The band structure calculations show semiconducting behavior for both the compounds. The theoretically calculated values of the band gaps are found to be strongly dependent on the nature of the functional representing the exchange correlations. Technologically significant optical parameters (e.g., dielectric function, refractive index, absorption coefficient, optical conductivity, reflectivity, and loss function) have been determined. Important conclusions are drawn based on the theoretical findings.
Publisher: Elsevier BV
Date: 09-2019
Publisher: Elsevier BV
Date: 12-2017
Publisher: Wiley
Date: 25-08-2017
Abstract: For the first time, we have reported in this study an ab initio investigation on elastic properties, Debye temperature, Mulliken population, Vickers hardness, and charge density of the two recently synthesized superconducting ScRhP and ScIrP pnictides. The optimized cell parameters show fair agreement with the experimental results. The mechanical stability of both ternary phosphides is confirmed via the calculated elastic constants. Both compounds are ductile in nature and damage tolerant. ScIrP is expected to be elastically more anisotropic than ScRhP. The estimated value of Debye temperature predicts that ScRhP is thermally more conductive than ScIrP and the phonon frequency in ScRhP is higher than that in ScIrP. Both pnictides are soft and easily machinable due to their low Vickers hardness. Moreover, the hardness of ScRhP is lower due to the presence of antibonding Rh–Rh in ScRhP. The metallic conductivity of ScRhP reduces significantly when Rh is replaced with Ir. The main contribution to the total density of states (TDOS) at Fermi‐level ( E F ) comes from d‐electrons of Sc and Rh/Ir in both pnictides. These two ternary compounds are characterized mainly by metallic and covalent bonding with little ionic contribution. The calculated superconducting transition temperatures fairly coincide with the reported measured values.
Publisher: Elsevier BV
Date: 04-2019
Publisher: Wiley
Date: 12-09-2022
Abstract: This study carries out density functional theory (DFT)‐based simulation in order to observe the effect of pressure (up to 120 GPa) on the various physical properties of boron (B) containing new MAX compounds Hf 2 InB 2 and Hf 2 SnB 2 . Structural parameters in ambient conditions show excellent concordance with prior experimental and theoretical data. A decreasing trend of lattice parameters with pressure is observed. The stability of the phases under pressure is determined by calculating the elastic constant using the Born stability criteria, and is found stable within the studied pressure range. Pressure's effect on the various elastic moduli is considered, and a linear response with pressure is observed. The brittle/ductile behavior under pressure is investigated, and a brittle to ductile phase transition is found. An opposite trend of elastic moduli with pressure is observed for Vickers hardness. The nonlinear variation of Vickers hardness with pressure has been interpreted in terms of Pugh ratio and density of states (DOS). A decreasing trend of the anisotropic indices is observed for Hf 2 InB 2 , while an increasing trend is observed for Hf 2 SnB 2 . The electronic and optical properties are also significantly influenced by the pressure. The results obtained at zero GPa have been compared with previous results and show significant agreement.
Publisher: Springer Science and Business Media LLC
Date: 28-01-2021
DOI: 10.1007/S42452-021-04214-2
Abstract: Intermetallic compounds with CaAl 2 Si 2 -type structure have been studied extensively due to their exciting set of physical properties. Among various alumo-germanides, MgAl 2 Ge 2 is the new representative of CaAl 2 Si 2 -type structures. Our previous study explores the structural aspects, mechanical behaviors and electronic features of intermetallic MgAl 2 Ge 2 . The present work discloses the results of optoelectronic, thermodynamic and vibrational properties of MgAl 2 Ge 2 via density functional theory-based investigations. The band structure calculations suggest that MgAl 2 Ge 2 possesses slight electronic anisotropy and the compound is metallic. The Fermi surface topology reveals that both electron- and hole-like sheets are present in MgAl 2 Ge 2 . The electron charge density map indicates toward the dominance of covalent bonding in MgAl 2 Ge 2 . The optical parameters are found to be independent of the state of the polarization of incident electric field. The large value of the reflectivity in the visible-to-ultraviolet region up to ~ 15 eV suggests that MgAl 2 Ge 2 might be a good candidate as coating material to avoid solar heating. The thermodynamic properties have been calculated using the quasi-harmonic Debye approximation. We have found indications of lattice instability at the Brillouin zone boundary in the trigonal $$P\\overline{3}m1$$ P 3 ¯ m 1 phase from the phonon dispersion curves. However, the compound might be stable at elevated temperature and as a function of pressure. All the theoretical findings herein have been compared with the reported results (where available). Various implications of our results have been discussed in detail. Graphic abstract
Location: Bangladesh
No related grants have been discovered for Md. Ashraf Ali,.