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In this work we studied the behavior of electron and hole energy levels in GaAs-AlwGa1-w As double quantum wells within the effective mass approach. The system studied was in presence of a uniform magnetic field. In our case, we considered a configuration in which the magnetic field is applied in the growth direction of the heterostructure. We present the explicit analysis to identify the no-correlated electron-hole transistion energy as a function of the Aluminium's concentration, heterostructure geometry and the applied magnetic field. [ABSTRACT FROM AUTHOR]

The effects of the applied hydrostatic pressure on both polaronic corrections to the energy and to the electron effectivemass are calculated in a GaAs/AlxGa1-xAs quantum well using degenerated second-order perturbation theory within the effective-mass approximation. In our calculations confined slab LO-phonon modes was taken into account. Results are for different well widths and Al concentrations as a function of the compressive stress along the growth direction of the structure. We have found that the energy of the electron ground state diminishes with the well width and with the applied hydrostatic pressure. Also, for intermediate values of well width, both polaronic corrections decreases with the pressure but increases with the well width. Howeve, we have found that polaronic effects in the quantum well are very small. [ABSTRACT FROM AUTHOR]

We have performed a theoretical study of electronic states, the parallel Landé g-Factor and the cyclotron effective-mass in a quantum dot(QD), assumed to be in the form of a pillbox, in the presence of an uniform magnetic field applied parallel to the pillbox axis. The quantum pillbox is assumed to consist of a finite length cylinder of GaAs material surrounded by vacuum, which corresponds to the infinite confinement model and also by Ga1--xAlxAs which describe the realistic finite potential confinement. The calculations have been performed by using the Kummer confluent hypergeometric functions. This study is performed for different radius and lengths of the cylindrical GaAs pillbox and the limit cases have been study to prove the validity of the model. Our results are in good agreement with previous theoretical results[1] in the limit geometry of a quantum well. [ABSTRACT FROM AUTHOR]

Within the framework of the Ginzburg-Landau theory is considered the superconductor state in a mesoscopic ring, with negligible thickness, in the presence of an applied magnetic field perpendicular to the plane of the ring, when the inner edge comes into contact with a medium with a finite de Gennes b parameter. It is shown that for small values orb there exist superconducting edge states only for magnetic fields greater than a critical field, which depends on b. This implies a reduction of the regions in the phase diagram where the Meissner paramagnetic effect exists. [ABSTRACT FROM AUTHOR]

We demonstrate that the defect mode in the bulk plasmon-polariton gap of one-dimensional defective metamaterial photonic crystals can be used to achieve a giant enhancement of more than four orders of magnitude in the second harmonic (SH) conversion efficiency only by changing the incidence angle. Furthermore, the one-dimensional photonic crystal may be designed in order for the SH wave to coincide with the edge of the Bragg gap or with the defect mode inside this gap, in which case the enhancement is even higher. Because of the robustness of the bulk plasmon-polariton gap to scaling effects, the present proposal may inspire different routes for frequency upconversion, signal filtering, and switching photonic devices. [ABSTRACT FROM AUTHOR]

We demonstrate a concept for the giant enhancement of the transverse magneto-optical Kerr effect (TMOKE) using bulk plasmon polariton (BPP) modes in non-magnetic multilayer hyperbolic metamaterials (HMMs). Since the BPP modes are excited through the attenuated total reflection (ATR) mechanism, using a Si-based prism-coupler, we considered a single dielectric magneto-optical (MO) spacer between the prism and the HMM. The working wavelength was estimated, using the effective medium approach for a semi-infinite dielectric-plasmonic multilayer, considering the region where the system exhibits type II HMM dispersion relations. Analytical results, by means of the scattering matrix method (SMM), were used to explain the physical principle behind our concept. Numerical results for giant TMOKE values (close to their maximum theoretical values, ±1) were obtained using the finite element method (FEM), applying the commercial software COMSOL Multiphysics. Our proposal comprises a simple and experimentally feasible structure that enables the study of MO phenomena in HMMs, which may find application in future nanostructured magnetoplasmonic metamaterials for active nanophotonic devices.

Emergent technologies that make use of novel materials and quantum properties of light states are at the forefront in the race for the physical implementation, encoding and transmission of information. Photonic crystals (PCs) enter this paradigm with optical materials that allow the control of light propagation and can be used for optical communication, and photonics and electronics integration, making use of materials ranging from semiconductors, to metals, metamaterials, and topological insulators, to mention but a few. Here, we show how designer superconductor materials integrated into PCs fabrication allow for an extraordinary reduction of electromagnetic waves damping, making possible their optimal propagation and tuning through the structure, below critical superconductor temperature. We experimentally demonstrate, for the first time, a successful integration of ferroelectric and superconductor materials into a one-dimensional (1D) PC composed of [Formula: see text] bilayers that work in the whole visible spectrum, and below (and above) critical superconductor temperature [Formula: see text]. Theoretical calculations support, for different number of bilayers N, the effectiveness of the produced 1D PCs and may pave the way for novel optoelectronics integration and information processing in the visible spectrum, while preserving their electric and optical properties.

We present a nonlinear transfer matrix method for studying the second-harmonic generation (SHG) in nonperiodic metamaterial photonic superlattices. A large enhancement of up to 5 orders of magnitude in SHG efficiency was observed for superlattices made with a Cantor-like quasiperiodic assembly of a nonlinear material and a metamaterial. The enhancement was found to depend much more on the electric field amplitude along the structure because of self-similarity effects than on the amount of nonlinear material, which opens the way to design superlattices for tailored applications in broad-band tunable lasers., Competing Interests: The authors declare no competing financial interest.

We have performed a theoretical study of the effects of the non-parabolicity and coupling barrier in between GaAs quantum wells on the conduction electron cyclotron effective mass and Landé [Formula: see text] factor under the action of a growth-direction applied magnetic field. Numerical calculations are performed within the effective mass approximation and taking into account the non-parabolicity effects for the conduction-band electrons, by means of the Ogg-McCombe effective Hamiltonian. The system consists of two GaAs quantum wells connected by a Ga(1 - x)Al(x)As barrier and surrounded by Ga(1 - y)Al(y)As material. We have found that both the [Formula: see text] factor and the cyclotron effective mass are sensitive to the coupling strength, that is the height and width of the barrier in between the GaAs quantum wells. This behavior is similar for every Landé [Formula: see text] factor and the cyclotron effective mass calculated for different Landau levels. It is noticeable that the splitting between the [Formula: see text] and [Formula: see text] cyclotron effective mass increases with the central barrier width and the growth-direction applied magnetic field. As in a single quantum well, we found that the electron Landé [Formula: see text] factor increases with the growth-direction applied magnetic field, comparing quite well with the experimental reports, and that the magnetic field plays an important role in decoupling the quantum wells of the system. Additionally, we have studied the electron cyclotron effective mass and Landé g factor as functions of the Landau levels, depending on the non-parabolicity. From this result one can infer that their population must be taken into account for a complete study of the band parameters as has been proposed in previous works. The present theoretical results are in very good agreement with previous experimental reports in the limiting geometry of a single quantum well.

The influence of an intense laser field on shallow-donor states in cylindrical GaAs-Ga(1-x)Al(x)As quantum-well wires under an external magnetic field applied along the wire axis is theoretically studied. Numerical calculations are performed in the framework of the effective-mass approximation, and the impurity energies corresponding to the ground state and 2p(±) excited states are obtained via a variational procedure. The laser-field effects on the shallow-donor states are considered within the extended dressed-atom approach, which allows one to treat the problem 'impurity + heterostructure + laser field + magnetic field' as a renormalized 'impurity + heterostructure + magnetic field' problem, in which the laser effects are taken into account through a renormalization of both the conduction-band effective mass and fundamental semiconductor gap.

The hydrostatic-pressure effects on the electron-effective Landé [Formula: see text] factor and g-factor anisotropy in semiconductor GaAs-Ga(1-x)Al(x)As quantum wells under magnetic fields are studied. The [Formula: see text] factor is computed by considering the non-parabolicity and anisotropy of the conduction band through the Ogg-McCombe effective Hamiltonian, and numerical results are displayed as functions of the applied hydrostatic pressure, magnetic fields, and quantum-well widths. Good agreement between theoretical results and experimental measurements in GaAs-(Ga, Al)As quantum wells for the electron g factor and g-factor anisotropy at low values of the applied magnetic field and in the absence of hydrostatic pressure is obtained. Present results open up new possibilities for manipulating the electron-effective g factor in semiconductor heterostructures.