Browsing by Author "Abbes, E. H."

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    First-principles investigation of magneto-electronic properties and band Jahn-Teller effects in NiCoMnSi1-xAlx quaternary Heusler
    (Oum-El-Bouaghi University, 2022) Abbes, E. H.; Abbassa, H.; Meskine, S.; Bouhamou, I.; Boukortt, A.
    Using ab initio calculations, density functional theory (DFT) calculations have been performed to investigate the electronic and magnetic properties of NiCoMnSi1-xAlx (x=0, 0.25, 0.50, 0.75 and 1) quaternary Heusler compounds. To check the evolution of band Jahn teller effect in quaternary Heusler alloy and known the main raison to get the ground state energy by deforming the martensitic phase, we focused our work on the structural stability related to the formation of a Heusler alloy from two different crystallographic structures (cubic and tetragonal), for different concentrations. The structural, electronic and magnetic properties are calculated for all concentrations in both cubic and tetragonally distorted structure. Variation of total energy versus volume indicates that the crystallographic structures shift the cubic shape from a concentration of 0.50, which can be essential due to the Jahn-Teller effect. Magnetic properties of all studied alloys give the total magnetic moment of 4.086 μB, 4.561 μB, 5.024 μB, 5.092 μB and 5.000 μB respectively. With an integer value of total magnetic moment, NiCoMnAl alloy has a 100% spin polarisation at Fermi level with a half-metallic behaviour.
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    The effect of uniaxial stress on structural and electronic properties in half-heusler FeVSb: ab-initio study
    (Oum-El-Bouaghi University, 2022) Benchehida, B.; Abbassa, H.; Meskine, S.; Abbes, E. H.
    From the first-principles calculations based on density functional theory with the generalized gradient approximation, structural, electronic and optical properties of FeVSb, half Heusler compound are calculated within the framework to understand the effect of both uniaxial and hydrostatic stress. The calculated total energy variation indicates that the ground state corresponds to the cubic structure for none magnetic (NM) state. The material undergoes a structural phase transition under a uniaxial pressure of 0.5 GPa, it is found very inferior than that under hydrostatic pressure (Bo Kong et al., Physica B. 406 (2011) 3003-3010). From both band structure and density of states, half Heusler alloy FeVSb is found to be a semiconductor with an energy gap of 0.34 eV. The study of the optical properties shows that the uniaxial stress contributes to the weakening of the optical properties of this material.