Modern Physics Letters B

In this paper, we calculate the Andreev bound state spectrum in a half-infinite superconducting wire with an arbitrary number of bands crossing the chemical potential. Electrons in the wire are affected by the asymmetric (Rashba) spin–orbit coupling due to the presence of a substrate. The normal state of the wire is assumed to have an antiunitary symmetry (time reversal or its combination with a point group operation), which may be broken by the superconducting order parameter and/or the boundary. The bound state spectrum is calculated without relying on any particular microscopic model, using the semiclassical approach with the boundary conditions described by a phenomenological scattering matrix.

The structural and optical characteristics of polystyrene (PS) and ZnO nanoparticles embedded in polystyrene as polymeric nanocomposite foils (PS/ZnO) were examined. The sol–gel process was utilized to make ZnO nanoparticles with a diameter of less than 50 nm. The solution casting process was used to prepare pure PS and PS/ZnO nanocomposite foils. The PS/ZnO nanocomposite foils were very transparent in the visible region as-synthesized, but due to substantial absorption in the UV area, absorbent peaks were formed at 264 nm and 364 nm, and these foils serve as UV absorbers. X-ray diffractometer (XRD) of ZnO embedded polystyrene nanocomposite foils studied the crystal structure of the flexible foils. Optical properties and optical constants including band gap were studied by transmittance, absorbance, and reflectance spectra that are obtained by UV–Vis spectrophotometer. The Wemple DiDomenico single oscillator model was used to estimate the dispersion energy parameters ($E_0$, $E_d$, ${𝜀}_0,{\lambda }_0,S_0)$, optical moments ($M_{-1}$, $M_{-3})$, the density of states ($N$/$m^{\ast }$), dispersion of refractive index ($n_0)$, and plasma frequency (${\omega }_p)$ of the investigated foils. Semi-empirical relations were used to estimate the nonlinear index of refraction ($n_2)$ and third-order optical nonlinear susceptibility (${\chi }^{(3)})$. PS/ZnO nanocomposite foils operate as UV absorbents and are a promising preference for photonic applications due to their optical characteristics.

The underwater photoelectric detection equipment mainly uses 532 nm laser as the light source, but the corresponding photocathodes like Na₂KSbCs, GaAs and GaAsP have a wide spectral response region and are easily affected by other signals. Thereby, GaAlAs are materials worth developing because of their adjustable band gap, which usually is used as a window layer of GaAs-based photocathode. In this paper, the finite difference time domain (FDTD) method is used to carry out nanostructure design simulations. The results show that GaAlAs with Al component of 0.63 can obtain the cutoff wavelength near 532 nm, which is an excellent photocathode material to meet the requirement of narrow-band spectral response of 532 nm laser. Furthermore, the light absorptance can be improved effectively by the quadrangular prism or cylinder nanostructured array prepared on the Ga${}_{0.37}$Al${}_{0.63}$As emission layer surface, and the maximum light absorptance can reach 96.2% at 532 nm for the cylinder nanostructure array with a height of 900 nm and a base width of 100 nm. Nevertheless, the reflection-mode Ga${}_{0.37}$Al${}_{0.63}$As photocathode with the quadrangular prism nanostructured array can be slightly influenced with incident angle of light.

The optoelectronic and magnetic behaviors of GeC monolayer after transition metals (TMs) adsorption have been systematically discussed using density functional theory. The calculated data illustrates that the optimal adsorption sites of Sc-, Ti-, V-, Cr-, Mn-, Fe-, and Co-GeC systems are all located at $T_{\mathrm{\text{Ge}}}$ site, while the Ni- and Cu-GeC systems are situated in $T_H$ site. The band structures of Ti-, Fe-, and Ni-GeC systems still remain nonmagnetic semiconductors, while the Sc-, Cr-, and Cu-GeC systems exhibit magnetic semiconductor behaviors, and the band gaps are 0.11 eV (Sc), 0.30 eV (Cr), and 0.57 eV (Cu), respectively. In particular, V- and Mn-GeC systems exhibit half-metallic characteristics, and Co-GeC system exhibits magnetic metal characteristics. And the magnetic moments of Sc-, V-, Cr-, Mn-, Co-, and Cu-GeC structures have been obtained to be 0.08, 1.00, 2.00, 1.00, 0.04, and 1.00 ${\mu }_B$, respectively. Furthermore, the charge transfer was exhibited between the GeC and TM. Especially, the work function of GeC can decrease greatly after TM adsorption, among them, the work function of Sc-GeC is 37.9% lower than that of GeC. Consequently, it indicates the usefulness of the TM-GeC system for the fabrication of spintronic and nanoelectronic devices.

We derive analytic expressions of Helmholtz free energy, crystal parameters, nearest neighbor distance and mean nearest neighbor distance between two atoms, volume and equation of state of metal and substitutional alloy with FCC structure on the basis of the statistical moment method. We perform numerical calculations of density and ratio of volume at pressure $P$ to volume at zero pressure for metals Al, Cu and substitutional alloy AlCu at temperature up to 1500 K and pressure up to 350 GPa when using the Mie–Lennard–Jones $n-m$ potential and the coordination sphere method. Our calculation results are compared with the experimental data, other theoretical calculations and molecular dynamics simulations.