Browsing by Author "Khenata, Rabah"

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    Effect of incorporation of chromium on electronic, optical and magnetic properties of KTaO3
    (Oum-El-Bouaghi University, 2021) Bettir, Karim; Bekhti Siad, Amaria; Baira, Melouka; Zouaneb, Chahrazed; Khenata, Rabah
    In this study, the structural, electronic, optical and magnetic properties of undoped and Cr3+ doped KTaO3 compounds are investigated using the full potential linearized augmented plane wave method. The exchange-correlation potential is treated with the generalized gradient approximation (GGA) and modified Becke-Johnson potential (TB-mBJ) to improve the electronic structure calculations. These two compound are found to be semiconductors with indirect band gaps. The optical transitions are investigated via dielectric function along with other related optical constants such as refractive index and absorption coefficient. KTaO3 compound display nonmagnetic behavior, whereas KTaO3 doped Chromium show a ferromagnetic ground state. The magnetic properties in this theoretical study is also helpful for designing transition metal such as Chromium doped perovskite materials like KTaO3 compound for spin electonics performance.
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    Optoelectronic And Magnetic Properties Of The Ortho-perovskite Gdruo3 Using Dft+u With Spin-orbit Coupling
    (Oum-El-Bouaghi University, 2018) Labdelli, Abbes; Meskine, Said; Boukortt, Abdelkader; Khenata, Rabah
    We have investigated the structural, magnetic, and optoelectronic properties of the ortho-perovskite GdRuO3 using the accurate full-potential linearized augmented plane wave (FP-LAPW) method based on the density functional theory (DFT). The generalized gradient approach (GGA) was used to treat the exchange and correlation potential while the GGA+U was found to correct the deficiencies of the GGA. The Hubbard U was taken to be 6 eV (an experimental value). Besides, the modified Becke–Johnson (mBJ) exchange potential was also adopted along in combination with the GGA+U approach (mBJ+U) to enhance the description of the electronic structure. The A-type antiferromagnetic phase of the compound GdRuO3 is more stable than the other magnetic phases. The calculated magnetic moments in GdRuO3 were found to emerge especially from the Gd-4f states electrons. The different values semiconductor gap obtained respectively with GGA+U and mBJ+U were 1.4269 eV and 2.9039 eV. These values were increased at 3.5355 eV with the investigation of spin–orbit coupling effects (SOC) on the electronic structure. The mBJ+U+SOC approximation was also used to calculate the optical properties by determining the complex dielectric function from which are derived the other parameters.