| 1. |
- Kibbou, M., et al.
(författare)
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The electronic, magnetic and electrical properties of Mn2FeReO6 : Ab-initio calculations and Monte-Carlo simulation
- 2020
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Ingår i: Journal of Magnetism and Magnetic Materials. - : ELSEVIER. - 0304-8853 .- 1873-4766. ; 495
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a theoretical study of the electronic, magnetic and electrical properties of double perovskite Mn2FeReO6 with a high Curie temperature so far in magnetic oxides was conducted, using several methods such as Ab-initio and Statistical Physics like Monte-Carlo Simulations (MCS). However, the first principles calculations showed a half-metallic behavior from the density of states and band structures calculation, using PBE + U (apply on the elements Mn, Fe, and Re respectively). The critical temperature obtained by MCS has a great similarity with the experimental results.
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| 2. |
- Benhouria, Y., et al.
(författare)
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Carbides-anti-perovskites Mn3(Sn, Zn)C : Potential candidates for an application in magnetic refrigeration
- 2020
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Ingår i: Physica. E, Low-Dimensional systems and nanostructures. - : Elsevier BV. - 1386-9477 .- 1873-1759. ; 124
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, the combination of the First-principles density functional theory (DFT) calculations and Monte Carlo (MC) methods are investigated on the structural, magneto-electronic and magneto-caloric properties of the anti-perovskite carbides Mn3XC with X = Sn, Zn. Firstly, the electronic band structure and total/partial density of state of both Mn3SnC and Mn3ZnC are computed and compared to other theoretical and experimental works. Our results reveal that both Mn3SnC and Mn3ZnC structures exhibit a metallic behavior and the valence (VB) and conduction (CB) bands overlap considerably. Additionally, the magnetic and magneto-caloric properties including heat capacity (C), the entropy change (ΔS), adiabatic temperature (ΔT) and the refrigerant capacity (RC) were studied under the magnetic field ranging between 0 and 5 T for both anti-perovskites. Our findings suggest that both anti-perovskite carbide (Mn3SnC and Mn3ZnC) can act as an effective substrate for magnetic refrigeration.
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| 3. |
- Bouziani, I., et al.
(författare)
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Ab initio study of electronic and optical properties of penta-SiC2 and-SiGeC4 monolayers for solar energy conversion
- 2020
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Ingår i: Superlattices and Microstructures. - : ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD. - 0749-6036 .- 1096-3677. ; 142
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Tidskriftsartikel (refereegranskat)abstract
- In the current study, we explore theoretically electronic and optical properties of penta-SiC2 and -SiGeC4 monolayers based on ab initio computations and utilizing modified Becke-Johnson generalized gradient-approximation (mBJ-GGA) within the density functional theory. The calculated results show that both 2D penta-SiC2 and -SiGeC4 are structurally stable, according to their negative formation energy. Furthermore, we have found that the penta-SiC2 and -SiGeC4 semiconductors show indirect and moderate band gaps of 1.75 and 1.62 eV by employing mBJGGA functional, respectively. Also, these systems present sigma- and pi-bond between two nearest neighbor carbon atoms by overlapping sp(2)-sp(2) and p-p orbitals, respectively, as well as an ionic bond between two nearest neighbor Si-C and Ge-C atoms. Additionally, we have shown that the considered compounds exhibit small reflectivity and high absorption peaks in visible region with the shift of absorption edge of 2D penta-SiGeC4 to the low energy visible region due to its small band gap compared to that of 2D penta-SiC2. These findings make both penta-SiC2 and -SiGeC4 monolayer semiconductors promising candidates for photovoltaic technology.
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| 4. |
- Bouziani, I, et al.
(författare)
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Electronic and optical properties of ZnO nanosheet doped and codoped with Be and/or Mg for ultraviolet optoelectronic technologies : density functional calculations
- 2020
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Ingår i: Physica Scripta. - : IOP PUBLISHING LTD. - 0031-8949 .- 1402-4896. ; 95:1
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Tidskriftsartikel (refereegranskat)abstract
- Theoretically, the density functional calculations have been effectuated for investigating electronic and optical properties of zinc oxide nanosheet doped and codoped with Be and/or Mg utilizing the generalized gradient approximation modified Becke-Johnson (GGA-mBJ) approach. The computed results show that the ZnBeO, ZnMgO and ZnBeMgO in nanosheet structure, referring to their low formation energy values, are more stable than those in bulk one. Furthermore, the bandgap of ZnO monolayer can be effectively modulated through substitution of Zn atoms by Be and/or Mg. In addition to that, by incorporating Be and/or Mg, the absorption peaks of ZnO nanosheet shift into the shorter UV-wavelength side as well as its reflectivity becomes lower. These results indicate that doping and codoping process of ZnO monolayer with Be and/or Mg are two efficient ways to modulate electronic and optical properties for ultraviolet optoelectronic technologies.
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| 5. |
- Bouziani, I., et al.
(författare)
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Electronic, optical and thermoelectric properties of two-dimensional pentagonal SiGeC4 nanosheet for photovoltaic applications : First-principles calculations
- 2021
-
Ingår i: Superlattices and Microstructures. - : Elsevier. - 0749-6036 .- 1096-3677. ; 158
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Tidskriftsartikel (refereegranskat)abstract
- In this theoretical study, based on the density functional theory, we investigate the electronic, optical and thermoelectric properties of SiGeC4 nanosheet, within the framework of mBJ-GGA approximation (modified Becke-Johnson generalized gradient approximation). The calculated results indicate that the two-dimensional SiGeC4 compound is energetically, dynamically, thermally and mechanically stable in the pentagonal structure and shows semiconductor character with indirect and moderate bandgap. Also, it is found that this two-dimensional system presents high absorption and low reflectivity as well as high photoconductivity in the visible range. Furthermore, it is shown that the studied compound exhibits good thermoelectric performance with high electrical conductivity and Seebeck coefficient. These results render the twodimensional pentagonal SiGeC4 nanosheet as strong absorber layer candidate in the next generation of photovoltaic devices.
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| 6. |
- Bouziani, I., et al.
(författare)
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Two-dimensional Janus Sn2SSe and SnGeS2 semiconductors as strong absorber candidates for photovoltaic solar cells : First principles computations
- 2021
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Ingår i: Physica. E, Low-Dimensional systems and nanostructures. - : Elsevier. - 1386-9477 .- 1873-1759. ; 134
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional materials provide new opportunities for the next generation of effective and ultrathin photovoltaic solar cells. Herein, we propose Janus monolayers of Tin monochalcogenides, especially Janus Sn2SSe (type TA) and SnGeS2 (type TB) nanosheets, as strong absorber candidates for solar energy conversion, referring to their excellent electronic and optical properties. Interestingly, based on the first-principles computations, both Janus Sn2SSe and SnGeS2 monolayers possess semiconductor character with indirect and moderate band gaps of 1.60 and 1.61 eV, respectively. Accordingly, the considered systems, Sn2SSe and SnGeS2 single-layers, have high absorption coefficient, reaching up to 49.7 and 62.5 mu m(-1), high optical conductivity of about 4513 and 3559 Omega(-1)cm(-1), as well as low reflectivity never exceed 34.6 and 38.5 % in visible region, respectively. Additionally, the maximum photovoltaic efficiency of single-junction solar cells based on SnGeS2 and Sn2SSe nanosheets can reach as high as 27.47 % and 28.12 %, respectively. The present outstanding results would motivate both theoretical and experimental researchers to deepen the study of the potential applications of twodimensional Janus materials based on Tin monochalcogenides in solar cell technology.
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| 7. |
- Haman, Z., et al.
(författare)
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Structural, electronic and optical properties of two-dimensional Janus transition metal oxides MXO (M = Ti, Hf and Zr; X = S and Se) for photovoltaic and opto-electronic applications
- 2021
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Ingår i: Physica. B, Condensed matter. - : Elsevier. - 0921-4526 .- 1873-2135. ; 604
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional Janus transition metal dichalcogenides structures have drawn increasing importance due to their remarkable properties for versatile applications in optoelectronic, photo-catalytic, thermo-electricity, piezoelectricity and spintronic. In this Paper, by employing the Ab-initio computations based on the density functional theory, the structural, electronic and optical properties of Janus MXO (M = Ti, Hf and Zr; X = S and Se) mono-layers are investigated utilizing full potential linearized augmented plane waves (FP-LAPW) method. The lattice parameters of the six Janus were computed, which are close to the previous theoretical results. The density of states and the electronic band structures were investigated for the first time using (GGA-PBE) approximation for the potential of the exchange and correlation. The optical parameters like complex dielectric function, refractive index, reflectivity, extinction and absorption coefficients of all Janus were performed. Our results reveal strong absorption coefficient and low reflectivity in the visible and ultraviolet regions, which make them candidates for opto-electronic and photovoltaic applications.
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| 8. |
- Kibbou, M., et al.
(författare)
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Cs2InGaX6 (X=Cl, Br, or I) : Emergent Inorganic Halide Double Perovskites with enhanced optoelectronic characteristics
- 2021
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Ingår i: Current applied physics. - : Elsevier BV. - 1567-1739 .- 1878-1675. ; 21, s. 50-57
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Tidskriftsartikel (refereegranskat)abstract
- During the last decade, Inorganic Halide Double Perovskite materials have attracted widespread interest as a promising eco-friendly and non-toxic alternative to lead based hybrid halide organic–inorganic perovskites materials, with outstanding Stability, Structural and electronic properties. In this study, First-Principles density functional theory (DFT) calculations were performed on the structural, stability, electronic and optical properties of the transition metal-based double perovskites materials Cs2InGaX6 (X = Cl, Br, or I). Our results reveal that all these materials exhibit excellent thermodynamic and structural stability owing to their negative formation energies and Goldsmith's factors. It is also observed that Cs2InGaCl6, Cs2InGaBr6, and Cs2InGaI6 materials exhibit band gaps calculated by different functional (GGA-PBE and TB-mpj) in visible-range between 0.89 and 3.24 eV. Furthermore, the computed optical properties reveal strong absorption in UV, visible, and IR range with high optical conductivity and low reflectivity. These obtained results predict that the three transition metal-based double perovskites materials carries promising application in nano-electronic and optoelectronic device applications and can be considered as photovoltaic absorber materials.
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