Browsing by Author "W. A. Yahya"

Now showing 1 - 19 of 19
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    Ab initio Studies of the Structural, Electronic and Mechanical Properties of Zn1−xCrxTe
    (2021-02) A. A. Audu; W. A. Yahya; A. A. Abdulkareem
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    Alpha decay half-lives of 171-189Hg isotopes using Modified Gamow-like model and temperature dependent proximity potential
    (2020-11) W. A. Yahya
    The alpha decay half-lives for $^{171-189}\mathrm{Hg}$ isotopes have been computed using the Gamow-like model (GLM), modified Gamow-like model (MGLM1), temperature-independent Coulomb and proximity potential model (CPPM), and temperature-dependent Coulomb and proximity potential model (CPPMT). New variable parameter sets were numerically calculated for the $^{171-189}\mathrm{Hg}$ using the modified Gamow-like model (termed MGLM2). The results of the computed standard deviation indicates that the modified Gamow-like model (MGLM2) and the temperature-dependent Coulomb and proximity potential model give the least deviation from available experimental values, and therefore suggests that the two models (MGLM2 and CPPMT) are the most suitable for the evaluation of $\alpha$-decay half-lives for the $\mathrm{Hg}$ isotopes.
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    Calculation of a complete set of spin observables for proton elastic scattering from stable and unstable nuclei
    (2018-07-14) W. A. Yahya; B. I. S. van der Ventel; B. C. Kimene Kaya; R. A. Bark
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    Comparison of double-folding effective interactions within the cluster model
    (2018) B. D. C. Kimene Kaya; S. M. Wyngaardt; T. T. Ibrahim; W. A. Yahya
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    Density-Dependent Parametrizations in B3Y-Fetal NN Interaction: Application to Alpha Decay
    (2024) W. A. Yahya; O. K. Azeez; J. T. Majekodunmi; G. D. Olawale
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    (Acta Physica Polonica A, 2024-04-03) A. A. Yahaya; W. A. Yahya; A. S. Ahmed; A. A. Sholagberu
    Device applications in magnetic media, spintronics, oxygen membranes, sensors, etc., are some of the uses of ferrite materials. In this work, we have studied the structural, electronic, magnetic, mechanical, and thermoelectric properties of Cs-based double perovskites Cs 2 AX 6 (A = Ge, Mn; X = Cl, I), using Quantum Espresso with generalized gradient approximation Perdew–Burke–Ernzerhof and Perdew– Burke–Ernzerhof in solids exchange–correlation functionals. The band structure results show that Cs 2 GeCl 6 and Cs 2 MnCl 6 are semiconductors with direct band gaps. However, there are bands crossing observed for Cs 2 GeI 6 from the conduction band minimum to the valence band maximum, indicating the metallic nature of the material. Moreover, Cs 2 MnI 6 has magnetic properties; it exhibits a metal- lic nature in the spin-up state and a semiconductor nature in the spin-down state, suggesting that it can be used in spintronics applications. The calculated total magnetic moment of Cs 2 MnCl 6 is 3.0µ B (for both Perdew–Burke–Ernzerhof and Perdew–Burke–Ernzerhof in solids), while for Cs 2 MnI 6 , the calculated total magnetic moments are 3.02µ B and 3.06µ B , for Perdew–Burke–Ernzerhof and Perdew– Burke–Ernzerhof in solids exchange–correlation functionals, respectively. The results of the mechanical properties calculations show that Cs-based double perovskites Cs 2 AX 6 (A = Ge, Mn; X = Cl, I) are mechanically stable. Cauchy’s pressure and Poisson’s, Frantsevich’s, and Pugh’s ratios of the studied materials confirm that Cs 2 MnCl 6 is brittle, while the remaining studied double perovskite materials are ductile. Electrical conductivity, thermal conductivity, Seebeck coefficients, power factor, and figure of merit are the thermoelectric parameters analyzed in this study. Seebeck coefficients, electrical con- ductivity, and power factor increase with the rise in temperature, and Cs 2 MnX 6 (X = Cl, I) double perovskite materials have higher values of electrical conductivity than Cs 2 GeX 6 (X = Cl, I). All the studied materials have positive type conductivity due to their positive Seebeck coefficient values.
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    Effect of hydrostatic pressure on opto-electronic, elastic and thermoelectric properties of the double perovskites Rb<sub>2</sub>SeX<sub>6</sub>(X=Cl,Br): a DFT study
    (2024-02-11) A. A. Yahaya; W. A. Yahya; I. A. Rahmon
    Double perovskites find applications across a diverse range of situations and varying pressure conditions. In this work, Quantum ESPRESSO code with a plane wave basis set was used to study the opto-electronic, elastic, and thermoelectric properties of Rb2SeX6 (X=Cl, Br) double perovskites under hydrostatic pressure (0 - 8 GPa). Perdew-Burke-Ernzerhof for Solids (PBESol) with generalized gradient approximation (GGA) was used as exchange-correlation functional. The band gap values of the materials decrease under hydrostatic pressure. Rb2SeCl6 has a band gap value of 2.44 eV at 0 GPa, 2.21 eV at 2 GPa. Above 2 GPa, the material has a metallic nature. Rb2SeBr6 has a band gap value of 1.56 eV at 0 GPa, but has a metallic nature under hydrostatic pressure (2 GPa to 8 GPa). The optical properties results indicate that the materials exhibit maximum absorption, high reflectivity, low optical loss in the visible and ultraviolet regions, good optical conductivity, and a refractive index suitable for use in opto-electronic applications. The materials are confirmed to be mechanically stable under all the hydrostatic pressure values studied. Electrical conductivity, thermal conductivity, and Seebeck coefficient (S ) values of the studied materials increase with an increase in hydrostatic pressure and temperature. The maximum value of S for Rb2SeBr6 is 0.248 x 103 (m V/k), while for Rb2SeCl6, maximum S = 0.175 x 103 (m V/k). The positive values of S suggest that the predominant charge carriers of Rb2SeCl6/Br6 are holes. Also, Rb2SeBr6 has a figure of merit (ZT) value of 3.44, while for Rb2SeCl6, ZT = 1.07. Since the values of ZT are greater than unity, the two double perovskite materials have good ZT values for thermoelectric device engineering. The results also suggest that Rb2SeBr6 is a better thermoelectric material than Rb2SeCl6.
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    Position and momentum information‐theoretic measures of the pseudoharmonic potential
    (2015-04-14) W. A. Yahya; K. J. Oyewumi; K. D. Sen
    In this study, the information‐theoretic measures in both the position and momentum spaces for the pseudoharmonic potential using Fisher information, Shannon entropy, Renyi entropy, Tsallis entropy, and Onicescu information energy are investigated analytically and numerically. The results obtained are applied to some diatomic molecules. The Renyi and Tsallis entropies are analytically obtained in position space using Srivastava–Niukkanen linearization formula in terms of the Lauricella hypergeometric function. Also, they are obtained in the momentum space in terms of the multivariate Bell polynomials of Combinatorics. We observed that the Fisher information increases with n in both the position and momentum spaces, but decreases with for all the diatomic molecules considered. The Shannon entropy also increases with increasing n in the position space and decreases with increasing . The variations of the Renyi and Tsallis entropies with are also discussed. The exact and numerical values of the Onicescu information energy are also obtained, after which the ratio of information‐theoretic impetuses to lengths for Fisher, Shannon, and Renyi are obtained. © 2015 Wiley Periodicals, Inc.
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    Quantum information entropies for the $$\ell $$ ℓ -state Pöschl–Teller-type potential
    (2016-04-14) W. A. Yahya; K. J. Oyewumi; K. D. Sen
    In this study, we obtained the position–momentum uncertainties and some uncertainty relations for the Pöschl–Teller-type potential for any . The radial expectation values of r −2 , r 2 and p 2 are obtained from which the Heisenberg Uncertainty principle holds for the potential model under consideration. The Fisher information is then obtained and it is observed that the Fisher-information-based uncertainty relation and the Cramer–Rao inequality hold for this even power potential. Some numerical and graphical results are displayed.
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    κ state solutions for the fermionic massive spin-½ particles interacting with double ring-shaped Kratzer and oscillator potentials
    (2014-04-12) K. J. Oyewumi; B. J. Falaye; C. A. Onate; O. J. Oluwadare; W. A. Yahya
    In recent years, an extensive survey on various wave equations of relativistic quantum mechanics with different types of potential interactions has been a line of great interest. In this regime, special attention has been given to the Dirac equation because the spin-½ fermions represent the most frequent building blocks of the molecules and atoms. Motivated by the considerable interest in this equation and its relativistic symmetries (spin and pseudospin), in the presence of solvable potential model, we attempt to obtain the relativistic bound states solution of the Dirac equation with double ring-shaped Kratzer and oscillator potentials under the condition of spin and pseudospin symmetries. The solutions are reported for arbitrary quantum number in a compact form. The analytic bound state energy eigenvalues and the associated upper- and lower-spinor components of two Dirac particles have been found. Several typical numerical results of the relativistic eigenenergies have also been presented. We found that the existence or absence of the ring shaped potential has strong effects on the eigenstates of the Kratzer and oscillator particles, with a wide band spectrum except for the pseudospin-oscillator particles, where there exist a narrow band gap.