International Journal of Modern Physics B

Two-dimensional (2D) materials with robust ferromagnetism properties have high potentials for application in the field of spintronics. However, extensively pursued 2D sheets, including pure graphene, monolayer BN, and layered transition metal dichalcogenides, are either nonmagnetic or weakly magnetic. The elastic, electronic and magnetic properties of monolayer CrN are calculated using the plane wave pseudo potential method based on first-principles density function theory. Upon determining through calculation that the structure of the monolayer CrN nanosheet is stable, its layer modulus ${\gamma }_0=330.2{\mathrm{\text{Nm}}}^{-1}$ shows that its strain resistance is stronger than that of graphene. Through strain analysis, materials with a monolayer CrN type of structure can be obtained. It is determined that 10% of the change in equilibrium area is still applicable to the 2D EOS, showing that this structure is quite stable. The spin-polarized electronic band structure is also calculated under different plane symmetry strains. The plane strain can be used to effectively adjust the metallic and magnetic properties of the material. Analyses of the band structure and density of states reveal that this material is half-metallic, where the origin of the ferromagnetism is related to $p$–$d$ exchange interactions between the Cr and N atoms. Monolayer CrN has semimetallic properties and strong ferromagnetic (FM) properties. The FM effect can enhance the stability of the material. The results show that monolayer CrN is a semimetallic material with good elastic properties and a strong FM property. This material is therefore expected to have good application rospects in the field of spin electronics.

Density functional theory’s (DFT) full potential linearized augmented plane wave method has been used to explore the structural and optoelectronic properties of bismuth-based tetragonal BiOCl, BiOBr and BiOI semiconductors. The generalized gradient approximation (GGA) has been used for structural optimization to approximate lattice constants and bulk moduli, which are found to be consistent with the current literature. Electronic band structures are computed using the modified Becke and Johnson generalized gradient approximation (mBJ) and within the Engel and Vosko generalized gradient approximation (EV-GGA), respectively. Based on the band structure analysis, these functional materials are indirect bandgap semiconductors with a wide range of potential applications. In addition, optical properties are also computed within mBJ and found to be appealing for optoelectronics and photocatalysis.

The Bohm–Staver description of sound waves in metals in the jellium model is generalized by taking into account not only the self-consistent electric field but also the second correlation moment of internal electric field that provides shear elasticity. The system of linearized equations that contains the second correlation moment of the field as a new variable is built. The wave equation is worked out and the velocities of longitudinal and transverse sound are found. The estimation of the field correlation value through the sublimation heat and the electronic Fermi-gas energy is offered for the metals. The velocities of transverse sound are found, which matches well the velocity obtained from the shear modules.

In this paper, the results of the first principles calculations within the framework of the density functional theory of the electronic spectrum of a GeS crystal are presented. The density of states and interband optical transitions are investigated. It was found that GeS compounds have semiconducting properties with a bandgap of 1.52 eV. The main contribution of the bands in the vicinity of the Fermi level is from the 3$p$ and 3$s$ states of the S and Ge atoms, respectively. The highest amplitude, about 2.3 eV ($𝜀\perp )$, is mainly associated with the interband optical transitions between the states $\mathrm{\text{S}}(p)+\mathrm{\text{Ge}}(s)\to \mathrm{\text{Ge}}(p)+\mathrm{\text{S}}(s)$. The results of the luminescence studies of GeS and GeS:Gd layered crystals at room-temperature are presented. A noticeable increase in the intensity of the luminescence radiation in GeS:Gd has been established. The reason for the increase in the effectiveness of photoluminescence is due to the overlapping of optical transitions of GeS at 695 nm wavelength with the radiation lines of Gd${}^{3+}$ion at that same energy.

The generalized exponential rational function method, which is one of the strong methods for solving nonlinear evolution equations, is applied to the conformable resonant nonlinear Schrödinger’s equation in this study. This equation plays a significant role in nonlinear fiber optics. It also has many important applications in photonic crystal fibers. The procedure implemented in this paper can be recommended in solving other equations in the field. All calculations and graphing are performed using powerful symbolic computational packages in Mathematica software. All calculations and graphing are performed using powerful symbolic computational packages in Mathematica software.

An integrated scheme of X-ray communication and detection is proposed in this paper, which is used for the detection of the unknown target inside the coating while communication. In contrast to the X-ray communication methods reported previously, simultaneous communication and radar detection have two distinct features. One is that both communication and detection signals share the same X-ray source and channel, so the spatial resources can be effectively utilized. The other is that X-ray can penetrate the metal shielding structure and detect the internal materials effectively. In order to achieve the above goals, the propagation feasibility of an X-ray signal in space and space sparse plasma environment are first analyzed. Simulation and experiment results indicate that the X-ray carrier can realize transmission without attenuation in space environment. Then, an X-ray radar and communication demonstration system is built to verify the detection ability of coated materials. Experimental results show that when the characteristic spectrum value of the unknown target is much higher than that of the rest shell, the spatial X-ray radar system can achieve more accurate discrimination. Finally, a conclusion is reached, and some feasible detection suggestions are provided for this simultaneous detection and communication system.

We designed a new type of $T$-type electroosmotic micromixer with variable modules (EMVMs). By applying 7V alternating current (AC) voltage to the EMVM, the mixing efficiency at different Reynolds number (Re) is discussed by changing the rotation angles of modules at different positions in different directions. We found that the mixing efficiency of the EMVM can reach 99% when the first block is rotated along the xz-axis. Then, we change the torsion angle of the same variable module and find that the mixing efficiency can reach 99.3% when the torsion is $0^{\circ }$. Finally, we change the voltage value and find that the mixing efficiency of the EMVM increases with the increase of voltage values.

Using the conditions obtained from various simple and complex models, the energy of the surface area was calculated with the help of electronic structural transitions and thermo-sublimation approximations occurring in yttrium oxide nanoparticles irradiated with different energy deuterium ions. The depth of penetration of deuterium ions of different energies into the yttrium oxide sample, the rate of energy loss, and the energy of the surface area under the influence of temperature sublimation were determined using basic methods. In addition, the screening radius and erosion rate were determined using the Sigmund and Thomas–Fermi shielding function.

In this study, different percentages of semiconducting zinc oxide nanoparticles (ZnONPs) are mixed with polyvinyl alcohol (PVA) to create flexible ZnO/PVA polymer nanocomposite films. The characteristics of the prepared films are investigated using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The XRD pattern shows that the ZnO/PVA composite films were successfully synthesized; while the SEM images show that the ZnONPs are homogeneously dispersed in the PVA polymer chain. Moreover, the DSC indicates an improvement in the thermal stability behavior with increased of ZnONPs concentration. The electrical conductivity, dielectric properties, electric modulus behavior, and the energy density efficiency of the pristine PVA and ZnO/PVA composite films are determined using an LCR meter in the frequency range 10²–10⁶ Hz. The dielectric constant of the composite film increased from 0.185 for pristine PVA to 1.389 for 9%ZnO/PVA, and the conductivity is improved from $1.93\times 10^{-5}$ S/cm to $7.98\times 10^{-5}$ S/cm. This work would open the road for utilizing ZnO/PVA flexible nanocomposite films for wide range of applications such as batteries, super-capacitor and energy storage devices.

A new method is proposed to obtain Gross–Pitaevskii equation by the chain of Bogoliubov–Born–Green–Kirkwood–Yvon (BBGKY) quantum kinetic equations. In that sense, we investigate the dynamics of a quantum system including infinite number of identical particles which interact via a (special) pair potential on the form of Dirac delta-function.