Қазақ ұлттық қыздар педагогикалық университеті / Казахский национальный женский педагогический университет

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Erratum to: «OPTICAL PROPERTIES OF LOW-DIMENSIONAL SYSTEMS: METHODS OF THEORETICAL STUDY OF 2D MATERIALS»
(2024-09-30)
G. A. Kaptagay
;
B. M. Satanova
;
Fatima U. Abuova
;
N. O. Koilyk
;
Aisulu U. Abuova
.
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First principles modelling of the N-doped Co0.5-terminated (0 0 1) Co3O4 surface
(Elsevier BV, 2020-01-01)
G. A. Kaptagay
;
Talgat M. Inerbaev
;
Abdirash T. Akilbekov
;
N. O. Koilyk
;
Aisulu U. Abuova
Цитирования (OpenAlex) 1Цитирования (OpenCitations) 1
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ELECTRONIC STRUCTURE, MAGNETIC PROPERTIES AND STABILITY OF HEUSLER ALLOYS Mn2Co1−x VxZ (Z = Al, Ga)
(2020-12-30)
Fatima U. Abuova
;
Талгат Муратович Инербаев
;
Aisulu U. Abuova
;
G. A. Kaptagay
;
N. A. Merali
Two sets of Heusler alloys of the type Mn2Co1−xVxZ (Z = Al, Ga) were studied by computer simulation methods using density functional theory. Changes in the absolute value and direction of the lattice ions' magnetic moments are investigated depending on the chemical composition. Topological analysis of the charge distribution on the crystal lattice atoms is carried out to explain the results obtained. It is shown that changes in the magnetic properties are determined by the system's charge ions' states. The fundamental difference between Al- and Ga-containing alloys is Ga ions' ability, in contrast to Al ions, to change their charge state as the vanadium concentration increases, which gives an additional degree of freedom for modifying the electronic structure of the studied compounds.
Цитирования (OpenAlex) 1Цитирования (OpenCitations) 1
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Structural, Electronic and Magnetic Properties of Mn2Co1-xVxZ (Z = Ga, Al) Heusler Alloys: An Insight from DFT Study
(Multidisciplinary Digital Publishing Institute, 2021-12-08)
Fatima U. Abuova
;
Талгат Муратович Инербаев
;
Aisulu U. Abuova
;
N. A. Merali
;
Nurgul S. Soltanbek
Structural, electronic, and magnetic properties of Mn2Co1-xVxZ (Z = Ga, Al, x = 0, 0.25, 0.5, 0.75, 1) Heusler alloys were theoretically investigated for the case of L21 (space group Fm3¯m), L21b (L21 structure with partial disordering between Co and Mn atoms) and XA (space group F4¯3m) structures. It was found that the XA structure is more stable at low V concentrations, while the L21 structure is energetically favorable at high V concentrations. A transition from L21 to XA ordering occurs near x = 0.5, which qualitatively agrees with the experimental results. Comparison of the energies of the L21b and XA structures leads to the fact that the phase transition between these structures occurs at x = 0.25, which is in excellent agreement with the experimental data. The lattice parameters linearly change as x grows. For the L21 structure, a slight decrease in the lattice constant a was observed, while for the XA structure, an increase in a was found. The experimentally observed nonlinear behavior of the lattice parameters with a change in the V content is most likely a manifestation of the presence of a mixture of phases. Almost complete compensation of the magnetic moment was achieved for the Mn2Co1-xVxZ alloy (Z = Ga, Al) at x = 0.5 for XA ordering. In the case of the L21 ordering, it is necessary to consider a partial disorder of atoms in the Mn and Co sublattices in order to achieve compensation of the magnetic moment.
Цитирования (OpenAlex) 13Цитирования (OpenCitations) 10
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Magnetic anisotropy and stability of Fe3Ga compounds
(L. N. Gumilyov Eurasian National University, 2021-12-10)
Талгат Муратович Инербаев
;
Aisulu U. Abuova
;
Alma K. Dauletbekova
;
Fatima U. Abuova
;
G. A. Kaptagay
The magnetic anisotropy energy and the stability of crystal modifications of D0 3 and L2 1 of Fe 3 Ga compounds are studied with the density functional theory methods. The magnetic anisotropy energy of the D0 3 structure is more than twice the same value for the L2 1 structure. The features in the electronic structure lead to the difference in the magnitude of spin-orbit interaction, explaining the found effect. The L2 1 structure is more thermodynamically stable in the entire range of the considered pressures. Under pressure, the considered crystal modifications of Fe 3 Ga lose their stability due to the appearance of imaginary frequencies in their phonon spectra.
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Theoretical study of the Ni–C system in the pressure range of 0–100 GPa
(2021-12-30)
Aisulu U. Abuova
;
Талгат Муратович Инербаев
;
Fatima U. Abuova
;
G. A. Kaptagay
This work is devoted to the search for stable compounds and structures in the Ni–C system in the pressure range of 0–100 GPa. Based on the density functional theory, a search for stable compounds and structures in the Ni–C system was carried out using modern algorithms for predicting crystal structures. As a result, one stable intermediate compound Ni3C with the structure of cementite, previously synthesized at 184 GPa, was revealed. Ni3C nickel carbide is dynamically stable, which is confirmed by the absence of imaginary modes in the phonon spectra. According to the results obtained, Ni3C is formed by the reaction of 3Ni + C ↔ Ni3Cabove 23 GPa and is stable up to at least 100 GPa. Spin-polarized calculations showed that the Ni3C has no magnetic moment in the entire pressure range. For carbon-rich compounds, performed calculations on the crystal structure prediction did not reveal any phase that would be energetically favorable relative to amixture of pure nickel and carbon. Also, it was shown that the most energetically favorable modification of metastable carbide Ni7C3 is orthorhombic Ni7C3-Pbca.
Цитирования (OpenAlex) 2Цитирования (OpenCitations) 2
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DFT studies of BaTiO3
(2023-06-30)
Талгат Муратович Инербаев
;
Zh. Ye. Zakiyeva
;
Fatima U. Abuova
;
Aisulu U. Abuova
;
S. A. Nurkenov
The structure of stable phases is investigated using first-principle calculations based on the functionals: LDA, GGA and newly developed general-purpose heavily constrained and appropriately normalized meta GGAfunctional (SCAN). The purpose of this study is to theoretically study the atomic displacements and band gap of the cubic, tetragonal, orthorhombic, rhombohedral perovskite phases for the comparison LDA, GGA-PBE and meta-GGA functionals using the density functional theory method. The obtained data of the density of states (DOS) showed that the values of the band gap energies are underestimated, and the DOS values show that the upper part (valence band) mainly consists of O 2p orbitals, the lower part (conduction band) consists of Ti 3d orbitals. The rhombohedral phase has a mixed composition of Ti states in the conduction band with a greater degree of 3dz2 than 3dxy. The values of the energies of the band gap (Egap) and the density of states show reasonable agreement with experimental and theoretical data. The LDA functional and, to a lesser extent, the GGA - PBE functional can also provide fairly accurate information about atomic displacements in these crystals. The values calculated by the SCAN functional do not differ much from the GGA and LDA functionals.
Цитирования (OpenAlex) 4Цитирования (OpenCitations) 3
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AB-INITIO CALCULATIONS OF RHOMBOHEDRAL BaTiO3 (111) SURFACE COMBINED WITH GRAPHENE FILMS
(2023-12-29)
B. M. Satanova
;
G. A. Kaptagay
;
A. P. Zharkymbekova
;
Fatima U. Abuova
;
Aisulu U. Abuova
Thin films of ABO3 perovskite ferroelectrics are important for many industrial applications, i.e., high-capacity memory cells, catalysis, optical waveguides, and integrated optics. The use of BaTiO3 for these industries and products is due to the variety of its surface structure and, accordingly, its electronic and chemical properties. Calculations of the surface characteristics of BaTiO3 from the first principles are useful for understanding processes that play a crucial role, such as surface reaction chemistry, surface phenomena, and adsorption surfaces. This study examined theoretical calculations related to the relaxed atomic structures of the surface of BaTiO3 (111).
Цитирования (OpenAlex) 1Цитирования (OpenCitations) 1
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EFFECT OF Rh-DOPING ON THE OPTICAL ABSORPTION OF THE (001) BaTiO3 SURFACE
(2024-06-30)
Zh. Ye. Zakiyeva
;
Talgat M. Inerbaev
;
Aisulu U. Abuova
;
Fatima U. Abuova
;
S. A. Nurkenov
Barium titanate is one of the most studied perovskite materials due to its substitution ability at both nodes of the crystal lattice, high dielectric constant, and stability. It has many outstanding characteristics, especially ferroelectric and dielectric properties, which can be improved by alloying, making this material suitable for a wide range of applications. In this paper, the effect of Rh doping on the structural, optical properties and electronic density of states of this compound is investigated. According to our calculations, Rh doping is a method that helps to increase the ability of BaTiO3 to absorb more light and reduce the excess potential required for water oxidation. Calculations of the electronic density of states were carried out using the hybrid functional HSE06. The analysis of optical properties was performed on the basis of matrix elements with a transient dipole moment. Studies have confirmed that the (001) BaTiO3 surface with terminated TiO2 has significant potential for use as a catalyst. Rh doping leads to an expansion of the spectrum of absorbed light over the entire visible range.
Цитирования (OpenAlex) 1Цитирования (OpenCitations) 1
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AB-INITIO CALCULATIONS OF THE RHODIUM-DOPED (001) SURFACE OF THE RHOMBOHEDRAL PHASE BaTiO3
(2024-06-30)
Zh. Ye. Zakiyeva
;
Talgat M. Inerbaev
;
Aisulu U. Abuova
;
Fatima U. Abuova
;
N. A. Merali
The advancement of effective, durable, and economically viable photocatalytic systems aimed at solar-driven water splitting into hydrogen and oxygen represents a strategically vital pathway for future fuel and chemical production from renewable sources. Water splitting is a promising strategy for the sustainable production of renewable hydrogen and for addressing the global energy and environmental crisis. However, the large-scale application of this method is limited by the low efficiency and high cost of solar water splitting systems. The search for economical, efficient, and stable photocatalysts is crucial in the development of solar water splitting technologies. Perovskite-based photocatalysts have recently attracted considerable attention for use in solar water splitting processes due to their simple structure and flexible composition. BaTiO3 is a promising photocatalyst because of its adjustable electronic structure. Initially considered a poor photocatalyst due to its wide band gap, this material has become the focus of various strategies aimed at reducing the band gap. In this paper, we study the effect of Rh doping on the electronic structure of the (001) BaTiO3 perovskite surface. Theoretical results show that Rh atoms can occupy both sites simultaneously, or only Ti sites, or Ba sites. The electronic structure was modeled for two conditions. When Rh atoms occupy one Ba position and one Ti position, the electronic structure shows the presence of an acceptor level within the band gap above the Fermi level, effectively reducing the band gap of the material.
Цитирования (OpenAlex) 1Цитирования (OpenCitations) 1

Қазақ ұлттық қыздар педагогикалық университеті / Казахский национальный женский педагогический университет

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