arXiv subjects

Moones Sabeti

Publications and source records attributed to Moones Sabeti.

4 recordsLinked to original sources

arXiv2020

Effect of annealing treatment on the structural, optical and magnetic properties of ZnSe thin films grown by spray pyrolysis

Many investigations and reviews show that II-VI compound semiconductor 1-D nanostructures have a great potential for the future electronic and optoelectronic applications. As an important II-VI semiconductor, ZnSe is one of the most significant materials with prominent applications in this issue. In the present work, we firstly provide a comprehensive investigation of the magnetic properties like magnetization and magnetic susceptibility of ZnSe nanostructures as a 1-D quantum many body. The magnetic study of this metal reveals a ferromagnetic-antifferomagnetic transition upon cooling. Magnetization shows a step-like behavior with pronounced plateaus in a specific magnetic field interval at low temperature. This subject has not been investigated in the previous works. In the experimental part, thin films of ZnSe are deposited on glass substrates (at two different substrate temperature) by the spray pyrolysis technique and annealed in vacuum at $400^\circ$C for 1 hour. Hereby, we investigate the morphology, structural and optical properties of ZnSe thin films using field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD) and UV-vis spectrophotometer measurements. XRD analysis reveal that annealed films grown on glass substrate at $400^\circ$C are polycrystalline in nature with cubic zincblene structure. By annealing, the grains size, the diameter and density of the particles increase. The UV-vis measurements display a red-shift of the absorption edge from the as-deposited to annealed ZnSe thin films as compared to its value for the ZnSe thin films. The band-gaps of the annealed samples are estimated about 2.71 eV, which are in consistence with the band gap of ZnSe thin films. The average transmittance of the annealed samples are over 80 $\%$ close to the infrared wavelength range.

physics.app-ph↗

arXiv2019

Magnetic properties of an antiferromagnetic spin-1/2 XYZ model in the presence of different magnetic fields: finite-size effects of inhomogeneity property

Magnetic and thermodynamic properties of the anisotropic XYZ spin-1/2 finite chain under both homogeneous and inhomogeneous magnetic fields are theoretically studied at low temperature. Using exact diagonalization method (ED), we study the magnetization, magnetic susceptibility and specific heat of the model characterized in terms of the finite correlation length in the presence of three different magnetic fields including longitudinal, transverse and transverse staggered magnetic fields. The magnetization, susceptibility and the specific heat of the model are investigated under two conditions separately: I) when the model is putted in the presence of homogeneous magnetic fields; II) when finite inhomogeneities are considered for all applied magnetic fields in the Hamiltonian. We show that for the finite-size XYZ chains at low temperature, the evident magnetization plateaus gradually convert to their counterpart quasi-plateaus when the transverse magnetic field increases. Moreover, the influence of the transverse and staggered transverse magnetic fields, and their corresponding inhomogeneities on the magnetization process, magnetic susceptibility, and specific heat are reported in detail. Our exact results illustrate that by altering the inhomogeneity parameters, magnetization plateaus gradually convert to their counterpart quasi-plateaus. The specific heat manifests Schottky-type maximum, double-peak and triple-peak, as well as, transformation between them by varying considered inhomogeneity parameters in the Hamiltonian.

cond-mat.stat-mech↗

arXiv2019

Electrocaloric effect in the two spin-1/2 XXZ Heisenberg edge-shared tetrahedra and spin-1/2 XXZ Heisenberg octahedron with Dzyaloshinskii-Moriya interaction

In the present paper, we consider two species of small spin clusters known as; two spin-1/2 Heisenberg edge-shared tetrahedra and spin-1/2 Heisenberg octahedron with the corresponding Dzyaloshinskii-Moriya terms in a longitudinal magnetic field, then we examine magnetization process and electric polarization of the models as functions of magnetic and electric fields at Low temperature using exact numerical diagonalization. Our exact results are in a good agreement with recent analysis carried out by J. Strečka and K. Kar{\v l}ova \cite{str18b,str17a}. It is demonstrated that the polarization behavior coincides the magnetization curves (including sequential intermediate plateaus), also it reflects the respective stepwise changes of ground-state phase transitions. We find that the polarization has significant effects on the magnetic field dependencies of the magnetization. Furthermore, we investigate other isothermal strategies such as cooling rate, magnetocaloric effect (MCE), as well as, electrocaloric effect(ECE) for both models. Since, new electrocaloric materials with high performance is of great interest and importance in condensed matter physics, here, we report on the ECE of the both aforedescribed spin-1/2 Heisenberg small clusters. We conclude that two spin-1/2 Heisenberg edge-shared tetrahedra is a material with significant reversible temperature change capability under an external electric field compared with the spin-1/2 Heisenberg octahedron, and can be used for cooling/heating process.

cond-mat.str-el↗

arXiv2016

Mechanical properties of metal decorated graphyne, graphyne-BN-yne, and BN-yne sheets

In this paper, the mechanical properties of two-dimensional structures of metal decoration systems of simple graphyne (CC), analogous system of BN sheet (BN-yne), also the graphyne-BN sheet (CC-BN-yne) was investigated. The properties such as Young and Bulk moduli were studied using Energy-Strain correlation. We introduced calculations based on density functional theory (DFT); the generalized gradient approximation (GGA) framework was used in this regard. The results demonstrated very competitive values for Young and Bulk moduli of the Pt decorated CC and BN-yne. However, the CC-BN-yne structure defined around 80% of Young and 77% of Bulk values of that of pure structures. Also Na decorated ones were examined and the results showed the same trend for all three structures. The CC-BN-yne defined the lowest values for either Young or Bulk moduli.

physics.comp-ph↗