Study of the Physical Properties of the EuCoA2_2As2_2 Compound: A DFT approach

In this study, we carried out an investigation of the EuCoA$_2$As$_2$ compound, focusing on its various physical properties. Our analysis covered the structural, magnetic, electronic, optical, thermodynamic and thermoelectric characteristics of this compound. To carry out this study, we used density functional theory (DFT) implemented in the Wien2k software package. To determine the exchange-correlation potential, we used the GGA-PBE (Perdew, Burke and Ernzerhof) approach, taking spin-orbit coupling (SOC) into account. Our results indicate that the EuCoA$_2$As$_2$ compound exhibits metallic behavior. In addition, we have determined that the compound's stable ground state is the ferromagnetic (FM) phase. We have also calculated the Debye temperature and the Gr\"uneisen parameter. In addition, we evaluated various optical properties, including electron energy loss, absorption coefficient, real and imaginary dielectric tensors, and real and imaginary optical conductivity. We found that the compound has excellent absorption characteristics in the low and mid ultraviolet (UV) spectra. In addition, we investigated the electrical conductivity, Seebeck coefficient, electronic conductivity and thermal conductivity of the lattice. The results revealed that the compound exhibits n-type behavior, with negative values for the Seebeck coefficient. These results are analyzed in detail and provide valuable information on the properties of the EuCoA$_2$As$_2$ compound. Additionally, the computed parameters were compared to those found in the literature. A good deals have been revealed with the existing results.Comment: 26 pages, 7 figures, 3 table

Structural, electronic, and magnetic properties of ZnTe doped with transition metal Mn

In this article, we examine the structure and the electronic, optical, and magnetic properties of ZnTe before and after doping with the transition metal Mn. The ab initio calculations of this compound were performed using the full potential linearized extended full potential planar waveform (FP-LAPW) in the context of density functional theory (DFT) implemented in the Wien2K code. The potential for exchange and correlation was addressed by the generalized gradient approximation (GGA) approximation. The electronic properties show that the ZnTe material exhibits semiconductor behavior before doping. As a result, it becomes semimetal after doping. The findings attained by Monte Carlo simulations display that the ZnMnTe material goes from an antiferromagnetic phase to the paramagnetic phase at the Neel temperature value TN =159.31 K

Edge wetting of an Ising three-dimensional system

The effect of edge on wetting and layering transitions of a three-dimensional spin-1/2 Ising model is investigated, in the presence of longitudinal and surface magnetic fields, using mean field (MF) theory and Monte Carlo (MC) simulations. For T=0, the ground state phase diagram shows that there exist only three allowed transitions, namely: surface and bulk transition, surface transition and bulk transition. However, there exist a surface intra-layering temperature $T_{L}^{s}$, above which the surface and the intra-layering surface transitions occur. While the bulk layering and intra-layering transitions appear above an other finite temperature $T_{L}^{b} (\ge T_{L}^{s})$. These surface and bulk intra-layering transitions are not seen in the perfect surfaces case. Numerical values of $T_{L}^{s}$ and $T_{L}^{b}$, computed by Monte Carlo method are found to be smaller than those obtained using mean field theory. However, the results predicted by the two methods become similar, and are exactly those given by the ground state phase diagram, for very low temperatures. On the other hand, the behavior of the local magnetizations as a function of the external magnetic field, shows that the transitions are of the first order type. $T_{L}^{s}$ and $T_{L}^{b}$ decrease when increasing the system size and/or the surface magnetic field. In particular, $T_{L}^{b}$ reaches the wetting temperature $T_{w}$ for sufficiently large system sizes.Comment: 11 Pages latex, 12 Figures P

Anisotropic effect on two-dimensional cellular automaton traffic flow with periodic and open boundaries

By the use of computer simulations we investigate, in the cellular automaton of two-dimensional traffic flow, the anisotropic effect of the probabilities of the change of the move directions of cars, from up to right ($p_{ur}$) and from right to up ($p_{ru}$), on the dynamical jamming transition and velocities under the periodic boundary conditions in one hand and the phase diagram under the open boundary conditions in the other hand. However, in the former case, the first order jamming transition disappears when the cars alter their directions of move ($p_{ur}\neq 0$ and/or $p_{ru}\neq 0$). In the open boundary conditions, it is found that the first order line transition between jamming and moving phases is curved. Hence, by increasing the anisotropy, the moving phase region expand as well as the contraction of the jamming phase one. Moreover, in the isotropic case, and when each car changes its direction of move every time steps ($p_{ru}=p_{ur}=1$), the transition from the jamming phase (or moving phase) to the maximal current one is of first order. Furthermore, the density profile decays, in the maximal current phase, with an exponent $\gamma \approx {1/4}$.}Comment: 13 pages, 22 figure

NUMERCAL STUDY OF A FOUR COMPONENTS SYSTEM

We have investigated numerically a statistical model of four component systems, which exhibit two critical temperatures, called the Ashkin-Teller model (ATM). The effects of, the anisotropy coupling, the single ion potential field and the mixed spin on the structure of the phase diagram have been studied. The model presents a rich variety of phase transitions which meet on tricritical or multicritical points. Different partially ordered phases with a partially broken symmetry appears at high temperatures. Their region of stability and their structure depend on the phase parameter space. The nature of critical lines which bound these partially ordered phases depends on the coupling parameters and the crystalline anisotropy".We have investigated numerically a statistical model of four component systems, which exhibit two critical temperatures, called the Ashkin-Teller model (ATM). The effects of, the anisotropy coupling, the single ion potential field and the mixed spin on the structure of the phase diagram have been studied. The model presents a rich variety of phase transitions which meet on tricritical or multicritical points. Different partially ordered phases with a partially broken symmetry appears at high temperatures. Their region of stability and their structure depend on the phase parameter space. The nature of critical lines which bound these partially ordered phases depends on the coupling parameters and the crystalline anisotropy

Hernie Inguinoscrotale de l’Uretère: Fait Clinique et Revue de la Littérature

la hernie intrascrotale de l’uretère est une situation rare, nous rapportons un cas clinique, compliqué d’hydronéphrose gauche chez un patient de 83ans, l’anomalie avait été reconnue en peropératoire.Mots clés: Hernie, de l’uretère, le scrotum, hydronéphros

Monte Carlo study of phase transitions and magnetic properties of LaMnO3

On the basis of Mean Field Approximation (MFA), Monte Carlo Simulations (MCS) and ab initio calculations we have studied the phase diagrams and magnetic properties of the bulk perovskite, LaMnO3 using Ising model Hamiltonian. It is shown that the antiferromagnetic coupling between next neighbors Mn ions is reponsible for a series of magnetic phase transitions. The transition temperature and the critical exponents obtained, in the framework of Monte Carlo simulations, using the experimental values of the exchange couplings and magnetic anisotropy are in agreement with the experimental ones. The exchange couplings deduced from ab initio calculations lead, by using Monte Carlo simulations, to a quantitative agreement with the experimental transition temperatures

Ground State Study of a Double Core-Shell Dendrimer Nanostructure

Based on a dendrimer graph theory, we investigate the ground state phase diagrams of a nanostructure formed by three spin types