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404 results on '"RESHAK, Ali H."'

18. Structure stability and magnetism in graphene impurity complexes with embedded V and Nb atoms

Author

Thakur, Jyoti, Kashyap, Manish K., Saini, Hardev S., and Reshak, Ali H.

Subjects
Condensed Matter - Materials Science
Abstract

First-principles density functional theory (DFT) study of embedding V and Nb atom in monovacant and divacant graphene is reported. Complete/almost complete spin polarization is verified for V/Nb embedding in MV/DV graphene. The origin of magnetism has been identified via interaction of 3d-states of embedded trnasition metal atom with p-states of inequivalent C atoms present in the vicinity of embedding site. Band structure analysis has been performed to address the semiconducting behavior of graphene in minority spin channel on embedding V/Nb atom. The isosurface plots also confirm the magnetic nature of present nanosystems. Our results reveal that these nanosystems have potential for futuristic applications such as spintronics, energy resources and high frequency transistors., Comment: 5 figures, 2 Tables

Published
2015
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22. Variation of cation-ligands XAl2Ge2(X = Pr, Nd, Gd, Tb) compounds by employing density functional theory

Author

Zada, Zeshan, Khan, Abdul Ahad, Reshak, Ali H., Ali, Dania, Faizan, Muhammad, Khan, Qaisar, Ismail, Muhammad, Murtaza, G., and Ramli, Muhammad M.

Abstract

•Band structures along with density of state approve metallic character of XAl2Ge2.•Ferromagnetic phase is more stable for calculating magnetic properties of XAl2Ge2.•Two approximations namely (PBE-GGA and GGA+U) are used.•Examination of magnetic properties confirms strong ferromagnetism of XAl2Ge2.

Published
2024
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32. A first principles study of Palladium-based full Heusler ferromagnetic Pd2MnSb compound.

Author

Zada, Zeshan, Khan, Abdul Ahad, Reshak, Ali H., Khan, Abdul Munam, Shakeel, Shakeel, Ali, Dania, Ismail, Muhammad, and Ramli, Muhammad M.

Subjects
HEUSLER alloys, GROUND state energy, MAGNETIC moments, DENSITY functional theory, DENSITY of states, MAGNETIC properties
Abstract

Density functional theory (DFT)-based calculations were used to calculate the physical properties of the full Heusler compound Pd2MnSb. The WIEN2K code is used with various approximations, such as generalized Gradient approximation (GGA) and (GGA + U) potentials, to investigate the structural, electronic, and magnetic responses. The unit volume cell is optimized to achieve the ground state energy level. The calculated band structure with both potentials confirms the metallic behavior of the selected compound, Pd2MnSb. The total density of states is also calculated by using these potentials, which confirms their metallic behavior. The calculated partial density of state with GGA and GGA + U potentials confirmed the particular contribution of atoms. We have calculated the magnetic properties with the GGA and GGA + U potentials to find out the total magnetic moment values that are suitable with the available experimental data. The calculated magnetic moments show that Pd2MnSb is a magnetized material. These investigated properties show that Pd2MnSb has metallic magnetized characteristics and is perfectly suitable for the applications of mass storage devices as a ferromagnetic material. [ABSTRACT FROM AUTHOR]

Published
2024
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34. Optical second harmonic generation in Yttrium Aluminum Borate single crystals (theoretical simulation and experiment)

Author

Reshak, Ali H., Auluck, S., Majchrowski, A., and Kityk, I. V.

Subjects
Condensed Matter - Materials Science
Abstract

Experimental measurements of the second order susceptibilities for the second harmonic generation are reported for YAl3(BO3)4 (YAB) single crystals for the two principal tensor components xyz and yyy. First principles calculation of the linear and nonlinear optical susceptibilities for Yttrium Aluminum Borate YAl3(BO3)4 (YAB) crystal have been carried out within a framework of the full-potential linear augmented plane wave (FP-LAPW) method. Our calculations show a large anisotropy of the linear and nonlinear optical susceptibilities. The observed dependences of the second order susceptibilities for the static frequency limit and for the frequency may be a consequence of different contribution of electron-phonon interactions. The imaginary parts of the second order SHG susceptibility chi_{123}^{(2)}(omega), chi_{112}^{(2)}(omega), chi_{222}^{(2)}(omega), and chi_{213}^{(2)}(omega) are evaluated. We find that the 2(omega) inter-band and intra-band contributions to the real and imaginary parts of chi_{ijk}^{(2)}\l(omega) show opposite signs. The calculated second order susceptibilities are in reasonably good agreement with the experimental measurements., Comment: 16 pages, 11 figures

Published
2008
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50. Predicting structural, optoelectronic and mechanical properties of germanium based AGeF3 (A = Ga and In) halides perovskites using the DFT computational approach.

Author

Husain, Mudasser, Rahman, Nasir, Amami, Mongi, Zaman, Tahir, Sohail, Mohammad, Khan, Rajwali, Khan, Abid Ali, Shah, Saima Ahmad, Saeedullah, Khan, Aurangzeb, Reshak, Ali H., Al-Shaalan, Nora Hamad, Alharthi, Sarah, Alharthy, Saif A., Amin, Mohammed A., and Tirth, Vineet

Subjects
PEROVSKITE, GERMANIUM, MECHANICAL behavior of materials, UNIT cell, HALIDES, LATTICE constants, SILICON alloys
Abstract

The increasing research of advanced materials with tremendous compositional and structural degrees of variation, identifying and discovering new materials for a specific application is a challenging task. Here, we report for the first time the predicted structural, optoelectronic, and mechanical properties of germanium based AGeF3 (A = Ga and In) halides Perovskites using the density functional theory computational approach. The tolerance factor "τ" is computed for both the materials and is found to be 0.91 for InGeF3 and 0.89 for GaGeF3 which indicates the structural stability of these perovskites crystal structures. The optimized crystal structural parameters for both the compounds are found to be 4.476 Å for InGeF3 and 4.422 Å for GaGeF3 by performing the fit using Birch–Murnaghan for the unit cell energy verses unit cell volume. Using the optimized lattice constants all the basic physical properties are computed. From the results of electronic properties it is determined that both the compounds depict a semiconductor nature with having an indirect (R-M) band gap of 1.48 eV for InGeF3 and 0.98 eV for GaGeF3. To explore the potential of these selected compounds the optical properties within the energy range of 0 eV up to 40 eV incident photon are computed for the prospective optoelectronic applications. Moreover, the mechanical properties for both the materials are computed using the IRelast package and the values of cubic elastic parameters estimates that AGeF3 (A = Ga and In) halides Perovskites are mechanically stable, hard to scratch, ductile and anisotropic. We are fully confident on the precision and accuracy of our reported results and reveals that the applications of germanium based AGeF3 (A = Ga and In) halides Perovskites compounds can be deemed in photovoltaic and in modern semiconducting industries. [ABSTRACT FROM AUTHOR]

Published
2023
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