Abdullah Chik
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Preferred name
Abdullah Chik
Official Name
Abdullah, Chik
Alternative Name
Chik, Abdullah
Chik, A
Chik, Abdullah bin
Main Affiliation
Scopus Author ID
15768692100
Researcher ID
EPX-6197-2022

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A Review of Genetic Algorithm: Operations and Applications

2024 , Abdullah Chik , Subash Chandra Bose Gopinath , Uda Hashim

This article presents a review of the Genetic Algorithm (GA), a prominent optimization technique inspired by natural selection and genetics. In the context of rapidly evolving computational methodologies, GA have gained considerable attention for their efficacy in solving complex optimization problems across various domains. The background highlights the growing significance of optimization techniques in addressing real-world challenges. However, the inherent complexity and diversity of problems necessitate versatile approaches like GA. The problem statement underscores the need to explore the underlying operations and applications of GA to provide a nuanced understanding of their capabilities and limitations. The objectives of this review encompass delving into the fundamental genetic operators, such as selection, crossover, and mutation, while examining their role in maintaining diversity and converging toward optimal solutions. Methodology-wise, a systematic analysis of existing literature is undertaken to distil key insights and trends in GA applications. The main findings show the adaptability of GA in tackling problems spanning engineering, economics, bioinformatics, and beyond. By facilitating the discovery of optimal or near-optimal solutions within large solution spaces, GA proves its mettle in scenarios where traditional methods fall short. The conclusion underscores the enduring relevance of GA in the optimization landscape, emphasizing their potential to remain a pivotal tool for addressing intricate real-world challenges, provided their parameters are fine-tuned judiciously to balance exploration and exploitation.

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First principles calculations of structural, electronic, mechanical and thermoelectric properties of cubic ATiO3 (A= Be, Mg, Ca, Sr and Ba) perovskite oxide

2021-09-01 , Adewale A.A. , Abdullah Chik , Tijjani Adam , Yusuff O.K. , Ayinde S.A. , Sanusi Y.K.

First principle calculation was performed to investigate material properties such as structural, electronic, mechanical and thermoelectric of ATiO3 (Be, Mg, Ca, Sr or Ba) a perovskite based oxide within density functional theory. Calculations were performed using PBEsol exchange correlation functional within generalized gradient approximation (GGA). Structural and electronic properties were elaborated since their effect gives information about the thermoelectric performance. The underestimate of band gap from DFT calculation were corrected by using DFT with Modified Becke and Johnson (mBJ). It was observed that compound with small band gap have higher electrical conductivity and at the same time, high performance of thermoelectric power factors. BeTiO3 was found to possess very low power factor due to its low value of Seebeck coefficient and electrical conductivity. Highest thermoelectric power factor was obtained in BaTiO3 at 1200 K. Elastic constant were used to explain the mechanical properties such as anisotropic, brittle characteristics, stiffness and many others.

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A DFT study of the optoelectronic properties of B and Be-doped Graphene

2024-02-01 , Agbolade L.O. , Dafhalla A.K.Y. , Zayan D.M.I. , Tijjani Adam , Abdullah Chik , Adewale A.A. , Subash Chandra Bose Gopinath , Uda Hashim

The electronic and optical properties of Boron (B) and Beryllium (Be)-doped graphene were determined using the ab initio approach based on the generalized gradient approximations within the Full potential linearized Augmented Plane wave formalism (FP-LAPW). Our findings demonstrated that doping at the edges of graphene is notably stable. In both systems, Be- doped graphene proves more efficient in manipulating the band gap of graphene. Both B and Be, induce P-type doping in graphene. B-doped graphene exhibits a negligible magnetic moment of 0.000742, suggesting its suitability for catalytic semiconductor devices. Conversely, Be-doped graphene displays a large magnetic moment of 1.045 μB, indicating its potential in spintronics. Additionally, this study elucidates the influence of the dopant atoms on the optical properties of graphene. These findings underscore a stable and controllable method for modelling graphene at its edges with B and Be atoms, opening new avenues in the design of these devices.

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Pengenalan kepada Pemprosesan Fizikal Mineral

2013 , Shahrizam Saad , Faizul Che Pa , Abdullah Chik , Mohamed Faisal, Mohamed Noor

Umum mengetahui kepentingan mineral dan logam dalam kehidupan manusia seharian. Walau bagaimanapun, tidak ramai yang mempunyai pemahaman jelas berkaitan dengan pemprosesan peringkat awal bahan ini. Situasi ini mengilhamkan para penulis buku ini untuk menghasilkan buku Pengenalan Kepada Pemprosesan Fizikal Mineral. Objektif utama penulisan buku ini adalah untuk memperbanyakkan bahan rujukan berkaitan pemprosesan mineral dalam medium Bahasa Melayu bagi kegunaan para pelajar dan masyarakat secara amnya. Pemprosesan mineral adalah satu kaedah yang digunakan untuk pengekstrakan bijih bagi mendapatkan mineral atau logam berharga yang dikenali sebagai konsentrat. Bermula daripada aktiviti perlombongan, bijih yang dilombong seterusnya akan menjalani beberapa peringkat proses untuk memisahkan konsentrat daripada mineral reja. Antara proses-proses yang terlibat adalah proses pengurangan saiz atau kominusi yang melibatkan proses penghancuran dan pengisaran. Proses penyaringan dan pengelasan pula bertujuan untuk mendapatkan taburan saiz yang dikehendaki untuk proses-proses seterusnya. Proses pemisahan konsentrat pula bergantung kepada ciri-ciri fizikal mineral seperti garviti tentu, kekonduksian dan magnetik manakala pemisahan yang bergantung kepada ciri-ciri kimia permukaan mineral pula adalah melibatkan proses pengapungan. Konsentrat yang terhasil daripada proses yang melibatkan pemisahan menggunakan medium air seterusnya akan menjalani proses penyahairan bagi menyingkirkan kandungan kelembapan konsentrat sebelum dihantar kepada pelebur untuk tujuan peleburan.

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Optoelectronic behavior of ZnS compound and its alloy: A first principle approach

2021-06-01 , Akeem Adekunle Adewale , Abdullah Chik , Tijjani Adam , Joshua Tolulope Majekodunmi , Durowoju M.O.

First principles calculations were employed to study the structural, electronic and optical properties of pristine ZnS and its alloy compounds; Zn0.75Cr0.25S, Zn0.75Ti0.25S & Zn0.50Cr0.25Ti0.25S. To investigate these, full potential linear augmented plane wave (FPLAPW) based on density functional theory (DFT) was adopted as implement in WIEN2K code by employing generalized gradient approximation (GGA) of the revised Perdew-Burke Erzenhoff (PBE) as exchange correlation function. Lattice constant, volume, bulk modulus and other physical parameters were calculated for structural properties. Variation in these parameters in crystal structure is related to difference in ionic radius of host and replaced atom. The results of band structure and density of states were determined for electronic properties. The pristine ZnS and Zn0.75Ti0.25S compounds are semiconductor in nature while Zn0.75Cr0.25S and Zn0.50Cr0.25Ti0.25S displayed metallic character. Optical parameters including absorption coefficient, energy loss function, complex refractive index; refractive index and extinction coefficient, and optical conductivity have been computed from the dielectric function at energy range of 0–25 eV. Static dielectric constant for ε1(ω) are found to be 6.61, 1811.89, 155.46 and 1446.14 in ZnS, Zn0.75Cr0.25S, Zn0.75Ti0.25S and Zn0.50Cr0.25Ti0.25S respectively. The mean peaks of absorption are found at energy range of ∼5–10.5 eV for all studied compounds. We obtained noble performance of optical conductivity of doped at 0–7 eV which is due to presence of 3d – orbitals in the doped compounds. Our results are compared with available theoretical calculations and the experimental data.

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Revisiting the optoelectronic properties of graphene : a DFT approach

2024-01 , L.O Agbolade , Alaa Kamal Yousif Dafhalla , A.Wesam Al-Mufti , Zainal Abidin Arsat , Tijjani Adam , Abdullah Chik , Subash Chandra Bose Gopinath , Muhammad Nur Aiman Uda , Uda Hashim

Understanding the atomic behaviour of pure graphene is crucial in manipulating its properties for achieving optoelectronics with high absorption indexes and efficiencies. However, previous research employing the DFT approach emphasised its zero-band gap nature, not its unique optical properties. Therefore, this study employed ab initio calculations to revisit the electronic, magnetic, and optical properties of pristine graphene using the WIEN2K code. The results reveal that the PBE-GGA valence and conduction bands cross at -0.7 eV. Our calculations demonstrated that the absorption coefficient of graphene has the strongest light penetration in the parallel direction. Furthermore, our results not only present the best possible propagation of light in pure graphene but also reveal that the linear relationship between the formation of the free electron carriers and the energy absorption is responsible for the high optical conductivity observed in pure graphene, as indicated by the peaks. Lastly, the metallic properties of graphene are reflected by the variation in spin up and down that appears, as evidenced by the total and partial densities of states, and the large refractive index attributed to its high electron mobility confirms its metallic nature.

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Recent advances in density functional theory approach for optoelectronics properties of graphene

2023 , A.L. Olatomiwa , Tijjani Adam , C.O. Edet , A.A. Adewale , Abdullah Chik , Mohammed Mohammed , Subash Chandra Bose Gopinath , Uda Hashim

Graphene has received tremendous attention among diverse 2D materials because of its remarkable properties. Its emergence over the last two decades gave a new and distinct dynamic to the study of materials, with several research projects focusing on exploiting its intrinsic properties for optoelectronic devices. This review provides a comprehensive overview of several published articles based on density functional theory and recently introduced machine learning approaches applied to study the electronic and optical properties of graphene. A comprehensive catalogue of the bond lengths, band gaps, and formation energies of various doped graphene systems that determine thermodynamic stability was reported in the literature. In these studies, the peculiarity of the obtained results reported is consequent on the nature and type of the dopants, the choice of the XC functionals, the basis set, and the wrong input parameters. The different density functional theory models, as well as the strengths and uncertainties of the ML potentials employed in the machine learning approach to enhance the prediction models for graphene, were elucidated. Lastly, the thermal properties, modelling of graphene heterostructures, the superconducting behaviour of graphene, and optimization of the DFT models are grey areas that future studies should explore in enhancing its unique potential. Therefore, the identified future trends and knowledge gaps have a prospect in both academia and industry to design future and reliable optoelectronic devices.

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Recent advances in density functional theory approach for optoelectronics properties of graphene

2023-03-01 , Olatomiwa A.L. , Tijjani Adam , Edet C.O. , Adewale A.A. , Abdullah Chik , Mohammed M. , Subash Chandra Bose Gopinath , Uda Hashim

Graphene has received tremendous attention among diverse 2D materials because of its remarkable properties. Its emergence over the last two decades gave a new and distinct dynamic to the study of materials, with several research projects focusing on exploiting its intrinsic properties for optoelectronic devices. This review provides a comprehensive overview of several published articles based on density functional theory and recently introduced machine learning approaches applied to study the electronic and optical properties of graphene. A comprehensive catalogue of the bond lengths, band gaps, and formation energies of various doped graphene systems that determine thermodynamic stability was reported in the literature. In these studies, the peculiarity of the obtained results reported is consequent on the nature and type of the dopants, the choice of the XC functionals, the basis set, and the wrong input parameters. The different density functional theory models, as well as the strengths and uncertainties of the ML potentials employed in the machine learning approach to enhance the prediction models for graphene, were elucidated. Lastly, the thermal properties, modelling of graphene heterostructures, the superconducting behaviour of graphene, and optimization of the DFT models are grey areas that future studies should explore in enhancing its unique potential. Therefore, the identified future trends and knowledge gaps have a prospect in both academia and industry to design future and reliable optoelectronic devices.

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Revisiting the Optoelectronic Properties of Graphene: A DFT Approach

2024-01-01 , Agbolade L.O. , Dafhalla A.K.Y. , Al-Mufti A.W. , Arsat Z.A. , Tijjani Adam , Abdullah Chik , Subash Chandra Bose Gopinath , Muhammad Nur Aiman Uda , Afnan Uda M.N. , Uda Hashim

Understanding the atomic behaviour of pure graphene is crucial in manipulating its properties for achieving optoelectronics with high absorption indexes and efficiencies. However, previous research employing the DFT approach emphasised its zero-band gap nature, not its unique optical properties. Therefore, this study employed ab initio calculations to revisit the electronic, magnetic, and optical properties of pristine graphene using the WIEN2K code. The results reveal that the PBE-GGA valence and conduction bands cross at-0.7 eV. Our calculations demonstrated that the absorption coefficient of graphene has the strongest light penetration in the parallel direction. Furthermore, our results not only present the best possible propagation of light in pure graphene but also reveal that the linear relationship between the formation of the free electron carriers and the energy absorption is responsible for the high optical conductivity observed in pure graphene, as indicated by the peaks. Lastly, the metallic properties of graphene are reflected by the variation in spin up and down that appears, as evidenced by the total and partial densities of states, and the large refractive index attributed to its high electron mobility confirms its metallic nature.

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Structural, electronic and thermoelectric properties of SrTiO₃ ceramic doped by lanthanum using first principles

2020 , Akeem Adekunle Adewale , Abdullah Chik , Ruhiyuddin Mohd Zaki

The Sr₀.9₂La₀.₀₈TiO₃ model compound was studied by means of the first-principles method grounded on the full-potential linearized augmented plane wave with the local orbital method as implement in WIEN2k. The structures, electronic and thermoelectric properties of the model compound are examined. Geometry optimization of Sr₀.9₂La₀.₀₈TiO₃ compound structure reveals the lattice constant of 3.9451 Å, which is the same as un-doped SrTiO₃. The direct bandgap of 2.48 eV (Γ-Γ) was measured from computed electronic band structure and its displayed density of states for Sr₀.9₂La₀.₀₈TiO₃ sample. Transport properties were calculated using BoltzTraP code as implemented in the WIEN2k code. The results were analyzed as a function of the variable temperatures, the density of state and chemical potential. Temperature and density of state variation with transport properties are in the same trend. Chemical potential proves material as n-type via Seebeck coefficient. The thermoelectric performance ZT of 0.05 was obtained at room temperature, while maximum value of 3.79 was recorded at 1200 K.

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