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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  • Publication
    First Principles Enhanced Electronic Band Structure of SrTiO₃ using DFT+U Method
    (Universiti Malaysia Perlis (UniMAP), 2019-01)
    Akeem Adekunle Adewale
    ;
    Abdullah Chik
    Density functional theory (DFT) technique was used to study the influence of Hubbard U on the calculated electronic properties of perovskite SrTiO₃. We used the Quantum Espresso (QE) software package with exchange-correction energy function within local density approximation for DFT and DFT+U calculations. The band structure, total and partial density of states (DOS and PDOS) were calculated. Three set of methods were adopted in the calculations: DFT without U, DFT+U with calculated U through linear response theory, and DFT+U with manually increment of U value. The calculated Hubbard U using linear response theory is 3.27 while selected U for manual increment method were chosen from 4.27 to 10.27 with an interval of 1. For DFT and DFT+U with calculated U, the calculated band gaps were 1.80 and 2.19 eV respectively. During increasing of U the calculated band gap were increasing from 2.43 eV (@U=4.27) and reaches peak of 3.06 eV (@U=8.27) which later reduce to 2.19 eV (@U=10.27). Therefore, DFT+U method with incremental Hubbard U resulted in better band gap value of 3.06 eV that is closer to the experimental result of 3.25 eV.
  • Publication
    DFT Study of Thermoelectric Performance of SrTiO₃ Doped by Tantalum
    (Universiti Malaysia Perlis (UniMAP), 2019-10)
    Akeem Adekunle Adewale
    ;
    Abdullah Chik
    ;
    Ruhiyuddin Mohd Zaki
    ;
    Faizul Che Pa
    ;
    Yeoh Cheow Keat
    ;
    Noorina Hidayu Jamil
    This paper deals with enhancement of thermoelectric performance of SrTiO₃ - a perovskite-based material by doping Ti-site with Ta. The electronic and the thermoelectric transport properties of doped SrTiO₃ were studied using the first principle calculation in full-potential of density functional theory. Spin-orbit coupling including Hubbard U parameter influences were observed in the investigation. Energy band structure and electron density of state were determined for electronic properties. The Seebeck coefficients, thermal conductivity, electrical conductivity as well as thermoelectric efficiency ZT were calculated for thermoelectric properties. The results of our calculations revealed that narrowing the bandgap of the material leads to the increase of thermoelectric efficiency ZT. At spin-orbit coupling with DFT+U method, ZT of 0.18 at 750 K were obtained and this is similar to the experimental data reported.
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