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Various physical properties (electronic, optical and thermoelectric) of cubic perovskite oxides $SrXO_3\; (X=Sc,\; Ge,\; Si)$ are investigated by using the density functional theory (DFT) within Wien2k code. This code is based on different approximations such as generalized gradient approximation GGA, PBEsol, LDA, WC and the modified Becke-Johnson exchange potentials (mBJ, nmBJ and unmBJ). Structural properties and the optimization have been calculated using PBEsol functional which showed a significant results that are in good agreement with the experimental ones. The results for physical properties such as electronic, thermoelectric and optical are analyzed in detail by using the nmBJ approximation. The obtained results present an opening gap for $SrSiO_3$, $SrGeO_3$ and a metallic behavior for $SrScO_3$. An average of transmittance which is about $94\%$ to $97\%$ was observed in the range of visible light. The increase of electrical conductivity with temperature confirms the effect of thermal agitation on the concentration of charges carriers using BolzTrap Package. Lastly a phonon dispersion was made and show that for $X=\; Ge$ and $Si$, the structure is relatively stable while $SrScO_3$ is dynamically unstable. These results prove the ability that these materials can be exploited in many applications and manufacturing of optoelectronics for Sensors., Comment: 22 pages, 16 figures

In both absence and presence of a circularly polarized monochromatic electromagnetic pulse, we have analyzed the electron-nucleon scattering process, where the nucleon is assumed to be spinless with a spherical shape. We have provided the theoretical calculation of the differential cross section (DCS) by using the Dirac-Volkov formalism. This research paper aims to provide two comparisons: We first compare the DCS in the absence of the laser field with its corresponding laser-assisted DCS. A second comparison is made between the electron-proton and electron-neutron scattering processes to study the effect of the laser on both processes. The results obtained about the effect of the laser field on the DCS and the electric form factor have been discussed for both scattering processes. We have found that the DCS is reduced when the laser field is applied for both processes. In addition, the form factor is also decreased by raising the incident electron energy in electron-proton scattering, but it increases in electron-neutron scattering. Moreover, the form factors for both scattering situations are unchanged by raising the laser field strength up to $10^{8}\,V/cm$., Comment: 17 pages, 6 figures

The electronic and local structural properties of CuO under pressure have been investigated by means of X-ray absorption spectroscopy (XAS) at Cu K edge and ab-initio calculations, up to 17 GPa. The crystal structure of CuO consists of Cu motifs within CuO$_4$ square planar units and two elongated apical Cu-O bonds. The CuO$_4$ square planar units are stable in the studied pressure range, with Cu-O distances that are approximately constant up to 5 GPa, and then decrease slightly up to 17 GPa. In contrast, the elongated Cu-O apical distances decrease continuously with pressure in the studied range. An anomalous increase of the mean square relative displacement (EXAFS Debye Waller, \sigma$^2$) of the elongated Cu-O path is observed from 5 GPa up to 13 GPa, when a drastic reduction takes place in \sigma$^2$. This is interpreted in terms of local dynamic disorder along the apical Cu-O path. At higher pressures (P>13 GPa), the local structure of Cu$^{2+}$ changes from a 4-fold square planar to a 4+2 Jahn-Teller distorted octahedral ion. We interpret these results in terms of the tendency of the Cu$^{2+}$ ion to form favorable interactions with the apical O atoms. Also, the decrease in Cu-O apical distance caused by compression softens the normal mode associated with the out-of-plane Cu movement. CuO is predicted to have an anomalous rise in permittivity with pressure as well as modest piezoelectricity in the 5-13 GPa pressure range. In addition, the near edge features in our XAS experiment show a discontinuity and a change of tendency at 5 GPa. For P < 5 GPa the evolution of the edge shoulder is ascribed to purely electronic effects which also affect the charge transfer integral. This is linked to a charge migration from the Cu to O, but also to an increase of the energy band gap, which show a change of tendency occurring also at 5 GPa.

Using toric Cartan matrices as abelian gauge charges, we present a class of stringy fractional quantum Hall effect (FQHE) producing some recent experimental observed filling factor values. More precisely, we derive the corresponding Chern-Simons type models from M-theory compactified on four complex dimensional hyper-K\"{a}hler manifolds X^4. These manifolds, which are viewed as target spaces of a particular N=4 sigma model in two dimensions, are identified with the cotangent bundles over intersecting 2-dimensional toric varieties V_i^2 according to toric Cartan matrices. Exploring results of string dualities, the presented FQHE can be obtained from D6-banes wrapping on such intersecting toric varieties interacting with R-R gauge fields. This string theory realization provides a geometric interpretation of the filling factors in terms of toric and Euler characteristic topological data of the compactified geometry. Concretely, explicit bilayer models are worked out in some details., Comment: 17 pages, latex

Laser assisted Coulomb scattering by relativistic electron and heavy electron (muon) is studied by using Salamin waves (Salamin 1993) in the Weak Field Approximation (WFA). Both electron and muon are described by the Dirac equation, with the anomalous magnetic moment effects fully included. The generalization of this paper to heavy electron (muon) gives interesting insights as to how the mass affects the magnitude of the differential cross sections. No significant difference in the muon's DCS with and without AMM effects was detected., Comment: I want to change the text

New insights into our understanding of the semirelativistic excitation of atomic hydrogen by electronic impact have been made possible by combining the use of polarized electron beams and intense laser field. The paper reviews relativistic theoretical treatment in laser-assisted electron scattering with particular emphasis upon spin effects. Different spin configurations for inelastic electron-atom collisions is also discussed. The role of laser field in such collision is of major importance and reveals new information on the dynamics of the collision process. The examined modern theoretical investigations of such relativistic laser-assisted collisions have shown that the need for experimental data is of a paramount importance in order to asses the accuracy of our calculations., Comment: one latex file and five figures

The excitation of H ($1s-2s$) by electron impact in the presence and in the absence of the laser field is studied in the framework of the first Born approximation. The angular variation of the laser-assisted differential cross section (DCS) for atomic hydrogen by electronic impact is presented at various kinetic energies for the incident electron. The use of Darwin wave function as a semirelativistic state to represent the atomic hydrogen gives interesting results when the condition $z/c\ll1$ is fulfilled. A comparison with the non relativistic theory and experimental data gives good agreement. It was observed that beyond (2700 $eV$) which represents the limit between the two approaches, the non relativistic theory does not yield close agreement with our theory and that, over certain ranges of energy, it can be in error by several orders of magnitude. The sum rule given by Bunkin and Fedorov and by Kroll and Watson \cite{22} has been verified in both nonrelativistic and relativistic regimes., Comment: 15 pages, 10 figures. arXiv admin note: substantial text overlap with arXiv:1211.0483; and text overlap with arXiv:physics/9911033 by other authors without attribution

Electron-impact ionization of atomic hydrogen with the electron's anomalous mag- netic moment (AMM) effects are examined. The formulas for the laser-assisted relativis- tic triple differential cross section (TDCS) in the coplanar binary geometry developed earlier by Y. Attaourti and S. Taj [Phys. Rev. A 69, 063411 (2004)] are used to check the consistency of our computations when the anomaly $\kappa$ is taken to be zero. We show that the contribution of the terms containing the AMM effects even in the first Born approximation has an important contribution, so it must be included in any reliable analysis. A full analytical calculation for the TDCS is presented., Comment: One latex file and five eps figures