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In this paper, we calculated the electronic and optical absorption coefficient of the Manning-like double quantum well under the external applied electric and magnetic fields. To calculate the linear and third-order nonlinear optical absorption coefficients is used two-level approach in the density matrix expansion. The findings show that the electronic structure can be adjusted by changing the well and barrier widths, the well depth, the coupling between the wells as well as applied external field intensities. In addition, direct and indirect exciton states in asymmetric double quantum wells with Manning-like potential under electric field are compared with experimental studies. From the obtained results, it is concluded that the Manning-like potential is an excellent strategy for modeling electronic states in asymmetric double quantum wells with steep potential barriers and also the Manning-like potential allows modeling interdiffusion effects at the interfaces of multiple heterostructures.

This study set out to introduce the optical nonlinearities of a intense laser-driven two-dimensional quantum ring subjected to external uniform magnetic field. Inclusion of the effect of non-resonant, high-frequency THz laser radiation is realised by the laser-dressed potential, whereas the total optical absorption coefficients, total relative refractive index changes and third-harmonic generation (THG) coefficient are inferred from the scheme of compact density-matrix formalism and iterative method. Our results reveal that the laser field smoothens the antidot region of the ring that consequences with remarkable modifications in the electronic structure and correspondingly the optical response of the system. We have found that the height and location of the resonant peaks of total optical absorption coefficient, total relative refractive index changes and THG coefficient can be controlled by the externally applied fields and system parameters. The tunability of the intersubband transitions could be beneficial for practical device application relying on the electronic optical transitions.

In this study, we present a detailed theoretical investigation of the effect of an externally applied magnetic field on the energy states 1s, 1p, 1d and 1f in the spherical quantum dot with finite and infinite confinement potentials. For both finite and infinite spherical quantum dot, the first four electron energies, Zeeman transition energies between these electronic states and optical absorption coefficients between the related states with and without magnetic field are investigated. The results show that the confinement potential, magnetic field and dot radius have a strong effect on energy states, Zeeman transition energies and absorption coefficients especially in the large dot radii. In the small dot radii, energy levels are relatively insensitive to the magnetic field because the spatial confinement of the electron prevails over the magnetic confinement. As Delta m changes from -1 to +1, the peak positions of the optical absorptions shift to higher energy values (blue shift). The absorption peaks for the infinite quantum dot are localised in higher photon energies those that of the finite quantum dot. The magnetic field causes that the degeneration of energies to be removed and the peak positions of transitions corresponding to Delta m = +1 shift towards to blue in contrast to the cases of Delta m = -1 and Delta m = 0.

In this study, the binding energies of an on-center and off-center hydrogenic donor impurity in a spherical quantum dot with finite confinement potential under an applied external magnetic field are investigated in detail by using the matrix diagonalization method in the effective mass approximation. Depending on the calculated energies and wave functions, the linear, third-order nonlinear and total optical absorption coefficients between the ground and several excited states are examined by the iterative method in the compact density matrix approximation for the two-level system. The combined effect of donor position, magnetic field and dot size on binding energies and optical absorption coefficients is observed. The results show that these effects cause significant changes on donor binding energy and optical absorption coefficients.

WOS: 000457720900013, We have investigated the binding energies of the s-symmetric ground and first excited shallow donor impurity states and the total 1s -> 2s absorption coefficient, including the first and third order corrections, in "12-6" tuned GaAs/GaAlAs double quantum well as a function of the impurity position, size of the structure, and the electric and magnetic field intensities. The obtained results show that the electronic and optical properties of tuned GaAs/GaAlAs double quantum well can be adjustable by an appropriate choice of the sample geometry, material parameters and applied external fields which will lead to new potential applications in optoelectronics., Colombian Agency: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia); Colombian Agency: Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2017-2018); Cumhuriyet University (CUBAP) [F-557], This research was partially supported by Colombian Agencies: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia) and Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2017-2018). This work used resources of the Centro Nacional de Processamento de Alto Desempenho em Sao Paulo (CENAPAD-SP). The authors are grateful to The Scientific Research Project Fund of Cumhuriyet University (CUBAP) under the project number F-557.

WOS: 000453499500082, We present a theoretical study on the linear and nonlinear optical properties in AlrGa1-rAs/GaAs asymmetric multiple step quantum wells (AMSQW) under the effects of a non-resonant intense laser field (ILF), electric, and magnetic field. Calculations are for the linear optical absorption and refractive index relative changes combined with the second and third harmonic generation. The potential profile is constructed as a function of the Aluminum concentration, so that the heterostructure has four steps of different concentration, width and height. The energy levels and corresponding wavefunctions are obtained by solving the Schordinger equation, for an electron, in the envelope function approach, with parabolic bands, and the effective mass approximations. The results show that variations in ILF, electric field and magnetic field have significant influences on the magnitude and peak energy positions of the SHG and THG coefficients. Therefore, we can conclude that the effects of ILF, electric and magnetic fields can be used to tune and control the SHG and THG in the range of the terahertz electromagnetic spectrurn., CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia); CODI-Universidad de Antioquia (project : "Efectos opticos intersubbanda, no lineales de segundo orden y dispersion Raman, en sistemas asimetricos de pozos cuanticos acoplados"); CODI-Universidad de Antioquia (project: "Efectos de capas delta dopadas en pozos cuanticos como fotodetectores en el infrarrojo"); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD exclusive dedication project 2018-2019); Universidad EIA; Universidad de Antioquia; Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (ALM exclusive dedication project 2018-2019), This research was partially supported by Colombian Agencies: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia and projects: "Efectos opticos intersubbanda, no lineales de segundo orden y dispersion Raman, en sistemas asimetricos de pozos cuanticos acoplados" and "Efectos de capas delta dopadas en pozos cuanticos como fotodetectores en el infrarrojo") and Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD exclusive dedication project 2018-2019 and ALM exclusive dedication project 2018-2019). The authors are grateful to the Universidad EIA and Universidad de Antioquia for its financial support through the EIA-UdeA-UdeM-project "Generacion de segundo armonico, rectificacion optica y dispersion Raman entre estados electronicos en pozos cuanticos acoplados". RLR and JPGP are grateful to Semillero de Investigacion Universidad EIA "Nanoestructuras Semiconductoras".

Within the structure of parabolic band and effective-mass approximations, the effects of magnetic and intense terahertz laser fields on the donor impurity-associated photoionization cross-section and nonlinear optical properties in delta-doped quantum well wires are studied using the variational method. The binding energy and photoionization cross-section as functions of doping concentrations, magnetic and terahertz laser fields are computed. The linear, third-order nonlinear and the corresponding total absorption coefficients and relative refractive index changes with a function of incoming photon energy for various doping concentrations, magnitude of terahertz laser and magnetic fields are investigated. The numerical results bring out that the donor impurity binding energy, photoionization cross-section, and nonlinear optical properties in the structure are strongly dependent on doping concentrations. In addition, it has been observed that the magnetic and intense terahertz laser fields cause considerable changes in the binding energy, photoionization cross section and nonlinear spectral properties of the system.

In this paper we are reporting the computation for the Nonlinear Optical Rectification (NOR) and the Second and Third Harmonic Generation (SHG and THG) related with electronic states of asymmetric double Si- δ -doped quantum well in a GaAs matrix when this is subjected to an in-plane ( x -oriented) constant magnetic field effect. The work is performed in the effective mass and parabolic band approximations in order to compute the electronic structure for the system by a diagonalization procedure. The expressions for the nonlinear optical susceptibilities, χ 0 ( 2 ) , χ 2 ω ( 2 ) , and χ 3 ω ( 3 ) , are those arising from the compact matrix density formulation and stand for the NOR, SHG, and THG, respectively. This asymmetric double δ -doped quantum well potential profile actually exhibits nonzero NOR, SHG, and THG responses which can be easily controlled by the in-plane ( x -direction) externally applied magnetic field. In particular we find that for the chosen configuration the harmonic generation is in the far-infrared/THz region, thus and becoming suitable building blocks for photodetectors in this range of the electromagnetic spectra.

WOS: 000411546800020, The effects of electric and magnetic fields on the second and third harmonic generation coefficients in a Morse potential quantum well are theoretically studied. The energy levels and corresponding wave functions are obtained by solving the Schrodinger equation for the electron in the parabolic band scheme and effective mass approximations and the envelope function approach. The results show that both the electric and the magnetic fields have significant influence on the magnitudes and resonant peak energy positions of the second and third harmonic generation responses. In general, the Morse potential profile becomes wider and shallower as gamma-parameter increases and so the energies of the bound states will be functions of this parameter. Therefore, we can conclude that the effects of the electric and magnetic fields can be used to tune and control the optical properties of interest in the range of the infrared electromagnetic spectrum. (C) 2017 Elsevier B.V. All rights reserved., CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (ALM); Universidad EIA; Universidad de Antioquia, This research was partially supported by Colombian Agencies: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia) and Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD and ALM exclusive dedication project 2016-2017). CAD and RLR are grateful to Universidad EIA and Universidad de Antioquia for financial support through the EIA-UdeA-UdeM-projects "Desarrollo de fotodetectores en el infrarrojo usando pozos cuanticos ajustables con dopamiento delta dentro del pozo".

WOS: 000398055300002, We investigate theoretically the intense laser-induced optical absorption coefficients and refractive index changes in a two-dimensional quantum pseudodot system under an uniform magnetic field. The effects of non-resonant, monochromatic intense laser field upon the system are treated within the framework of high-frequency Floquet approach in which the system is supposed to be governed by a laser-dressed potential. Linear and nonlinear absorption coefficients and relative changes in the refractive index are obtained by means of the compact-density matrix approach and iterative method. The results of numerical calculations for a typical GaAs quantum dot reveal that the optical response depends strongly on the magnitude of external magnetic field and characteristic parameters of the confinement potential. Moreover, we have demonstrated that the intense laser field modifies the confinement and thereby causes remarkable changes in the linear and nonlinear optical properties of the system.

WOS: 000376213000005, We investigate the effects of Rashba spin-orbit interaction on the optical absorption coefficients and refractive index changes associated with transitions between the first two lower-lying electronic levels in double quantum wire. The wire system represented by a symmetric, double quartic-well confinement potential is subjected to a perpendicular magnetic field. The analytical expressions of the linear and third-order nonlinear optical absorption coefficients and refractive index changes are obtained by using the compact density matrix formalism and iterative scheme. Optical properties are investigated as a function of structural parameter, magnetic field, Rashba spin-orbit interaction and photon energies. Numerical results reveal that competing effects between spin-orbit interaction and magnetic field modify strongly the optical properties and can be altered by these parameters. (C) 2016 Elsevier Ltd. All rights reserved., Scientific and Technological Research Council of Turkey [TUBITAK BIDEB 2211], The authors Y. Karaaslan and B. Gisi would like to thank the Scientific and Technological Research Council of Turkey (TUBITAK BIDEB 2211) for doctoral scholarship.

WOS: 000372559600045, We investigate the electronic structure, spin and transport properties of double quantum wires formed by a symmetric, double quartic-well potential subjected to an in-plane magnetic field by taking into account Rashba and Dresselhaus spin-orbit couplings. The energy dispersion relation of the system is analyzed for different strengths of spin-orbit interactions, magnitude and direction of magnetic field. Our numerical results reveal that the existence of aforementioned parameters modifies strongly the energy band structure, introduces a wave vector dependence to energies and also leads to crossings and anticrossings between subbands. This complex structure of energy dispersion gives rise to the appearance of square-wave like oscillations in the conductance. The spin-orbit couplings, magnetic field, potential profile and Fermi energy of an electron significantly affect the depth and width of conductance steps. Moreover, we found that the competing effect between spin-orbit couplings and magnetic field leaves its marks on the spin texturing. (C) 2015 Elsevier Ltd. All rights reserved., Scientific and Technological Research Council of Turkey [TUBITAK BIDEB 2211], The authors B. Gisi and Y. Karaaslan would like to thank the Scientific and Technological Research Council of Turkey (TUBITAK BIDEB 2211) for doctoral scholarship. This work has been completed at the Dokuz Eylul University, Graduate School of Natural and Applied Sciences and is the subject of the forthcoming Ph.D. Thesis of Bircan Gisi.

WOS: 000457753000024, PubMed ID: 30723242, The features of the electron energy spectrum in eccentric two-dimensional GaAs-AlGaAs quantum rings of circular shape are theoretically investigated taking into account the effect of externally applied magnetic and intense laser fields. Analytical expressions for the laser-dressed confining potential in this kind of quantum ring geometry are reported for the first time. Finite element method is used to solve the resulting single-particle effective mass two-dimensional partial differential equation. It is shown that the allowed level spectrum is greatly influence by the external probe as well as by the breaking of geometric symmetry related to the changes in eccentricity. In presence of an intense laser field, the conduction band confining profile suffers strong modifications along the structure, with an additional contribution to symmetry breaking. These modifications of electronic quantum states reflect in the intraband optical absorption. Accordingly, the features of the intraband transitions are discussed in detail, revealing the significant influence of the magnetic field strength and laser field intensity and polarization, together with eccentricity, in the allowing of ground-to-excited states transitions and their corresponding intensities., Universidad EIA; CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia); CODI-Universidad de Antioquia (project "Efectos de capas delta dopadas en pozos cuanticos como fotodetectores en el infrarrojo"); CODI-Universidad de Antioquia (project "Efectos opticos intersubbanda, no lineales de segundo orden y dispersion Raman, en sistemas asimetricos de pozos cuanticos acoplados"); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2018-2019); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (ALM-exclusive dedication project 2018-2019); Colombian Agency El Patrimonio Autonomo Fondo Nacional de Financiamiento para la Ciencia, la Tecnologa y la Innovacion, Francisco Jose de Caldas-COLCIENCIAS; Mexican Conacyt [206772]; Universidad de Antioquia, J.A. Vinasco acknowledges the support and fruitful cooperation with Prof. Dr. A. Radu during his doctoral stay at the Department of Physics, "Politehnica" University of Bucharest, where part of this work was done. This research was partially supported by Colombian Agencies: Universidad EIA, CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia and projects "Efectos de capas delta dopadas en pozos cuanticos como fotodetectores en el infrarrojo" and "Efectos opticos intersubbanda, no lineales de segundo orden y dispersion Raman, en sistemas asimetricos de pozos cuanticos acoplados"), and Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2018-2019 and ALM-exclusive dedication project 2018-2019). This work used resources of the Centro Nacional de Processamento de Alto Desempenho em Sao Paulo (CENAPAD-SP). J.A. Vinasco acknowledges the doctoral financial support from the Colombian Agency El Patrimonio Autonomo Fondo Nacional de Financiamiento para la Ciencia, la Tecnologa y la Innovacion, Francisco Jose de Caldas-COLCIENCIAS. M.E. Mora-Ramos acknowledges support from Mexican Conacyt through Grant 206772. The authors are grateful to the Universidad EIA and Universidad de Antioquia for financial support through the EIA-UdeA-UdeM-project "Generacion de segundo armonico, rectificacion optica y dispersion Raman entre estados electronicos en pozos cuanticos acoplados".

WOS: 000432750900015, The third-harmonic generation (THG) coefficient for a laser-driven quantum dot with an on-center Gaussian impurity under static magnetic field is theoretically investigated. Laser field effect is treated within the high-frequency Floquet approach and the analytical expression of the THG coefficient is deduced from the compact density-matrix approach. The numerical results demonstrate that the application of intense laser field causes substantial changes on the behavior of THG. In addition the position and magnitude of the resonant peak of THG coefficient is significantly affected by the magnetic field, quantum dot size and the characteristic parameters of the impurity potential.

The combined effects of electric and magnetic fields on the optical absorption coefficients and refractive index changes related to the intersubband transitions within the conduction band of asymmetric GaAs / Ga 1 - x Al x As double inverse parabolic quantum wells are studied using the effective-mass approximation and the compact density-matrix approach. The results are presented as a function of the incident photon energy for the different values of the electromagnetic fields and the structure parameters such as quantum well width and the Al concentration at the well center. It is found that the optical absorption coefficients and the refractive index changes are strongly affected not only by the magnitudes of the electric and magnetic fields but also by the structure parameters of the system.

WOS: 000357233800004, The effects of electric and magnetic fields on the nonlinear optical rectification and second harmonic generation coefficients related with intersubband transitions in a semi-parabolic quantum well under intense laser field are theoretically studied. The energy levels and corresponding wave functions are obtained by solving the conduction band Schrodinger-like equation in the parabolic approximation and the envelope function approach. Numerical calculations are presented for a typical GaAs/Ga1-xAlxAs quantum well. The results show that both the non-resonant intense laser field and the static external fields have significant influences on the magnitude and resonant peak energy positions of the coefficients under study. (C) 2015 Elsevier Ltd. All rights reserved.

WOS: 000451653700009, In the present study, we theoretically reported the effects of applied external fields, such as intense laser field and electric and magnetic fields, on the optical absorption coefficient and refractive index changes in the Tietz-Hua potential quantum well by the compact density-matrix approach. For this, we first calculated the subband energy levels and their corresponding electronic wave functions of the structure by solving the one-dimensional Schrodinger equation within the framework of the effective mass and envelope wave function approximations. Our theoretical results show that the optical absorption coefficient and refractive index changes in the Tietz-Hua potential quantum well are sensitive to the applied external fields. The absorption spectra in the structure can be adjusted depending on the purpose by changing the strength of the applied external fields, and these results can be used to tune and control the electronic and optical properties of the Tietz-Hua potential quantum well., Scientific Research Project Fund of Cumhuriyet University (CUBAP) [TEKNO-019], The authors are grateful to the Scientific Research Project Fund of Cumhuriyet University (CUBAP) under the project number TEKNO-019.

WOS: 000423886800011, We study the influence of electric field on the electronic energy band structure, zero-temperature ballistic conductivity and optical properties of double quantum wire. System described by double well anharmonic confinement potential is exposed to a perpendicular magnetic field and Rashba and Dresselhaus spin-orbit interactions. Numerical results show up that the combined effects of internal and external agents cause the formation of crossing, anticrossing, camel-back/anomaly structures and the lateral, downward/upward shifts in the energy dispersion. The anomalies in the energy subbands give rise to the oscillation patterns in the ballistic conductance, and the energy shifts bring about the shift in the peak positions of optical absorption coefficients and refractive index changes. (C) 2017 Elsevier B.V. All rights reserved., Scientific and Technological Research Council of Turkey [TUBITAK BIDEB 2211], The authors Y. Karaaslan and B. Gisi would like to thank the Scientific and Technological Research Council of Turkey (TUBITAK BIDEB 2211) for doctoral scholarship.

WOS: 000414180500020, In this study, the effects of the electric and magnetic fields as well as structure parameter-gamma on the total absorption coefficient, including linear and third order nonlinear absorption coefficients for the optical transitions between any two subband in the Tietz-Hua quantum well have been investigated. The optical transitions were investigated by using the density matrix formalism and the perturbation expansion method. The Tietz-Hua quantum well becomes narrower (wider) when the gamma - structure parameter increases (decreases) and so the energies of the bound states will be functions of this parameter. Therefore, we can provide the red or blue shift in the peak position of the absorption coefficient by changing the strength of the electric and magnetic fields as well as the structure parameters and these results can be used to adjust and control the optical properties of the Tietz-Hua quantum well., Scientific Research Project Fund of Cumhuriyet University (CUBAP) [F-516], The authors are grateful to The Scientific Research Project Fund of Cumhuriyet University (CUBAP) under the project number F-516.

WOS: 000410633400033, In this research, we present the effects of high-frequency intense laser field on the third-harmonic generation associated with intersubband transitions in a two-dimensional quantum pseudodot system subjected to an uniform external magnetic field. Non-resonant monochromatic laser radiation with circular polarization is considered within the framework of high-frequency Floquet approach. On the basis of the compact-density matrix approach and an iterative method, the third-harmonic generation coefficient is calculated. The results presented for a GaAs quantum dot show that: (i) the position and magnitude of the resonant peak of third-harmonic generation depend strongly on magnetic field, the chemical potential and zero-point of pseudoharmonic potential; (ii) the strength of intense laser field modifies the confinement potential which results in considerable changes in the nonlinear optical response of the system.

We report the optical properties of a laser-driven two-dimensional quantum dot with a hydrogenic impurity exposed to a magnetic field. The effective mass approximation is used to bring out the effect of an intense laser field, resulting in dressed Coulomb and confinement potentials, on the one-electron energy levels and wave functions. The results obtained suggest that the action of the laser field leads to crucial changes in the energy spectra of the system and the impurity binding energy. Furthermore, the position and the height of the resonant peaks of the absorption coefficients and refractive index changes depend strongly not only on the geometrical confinement strength but also on the magnetic field and laser radiation through the “laser-dressed” potential.

WOS: 000401386400032, In the present work, the effects of the non-resonant intense laser field, electric and magnetic fields on the optical properties, such as linear, third order nonlinear and the total optical absorption coefficient and refractive index changes associated with the intersubband transitions between the ground and the first excited states in the n-type double delta-doped GaAs quantum well is theoretically studied by solving the Schrodinger equation in the laser-dressed confinement potential within the framework of effective mass approximation. The analytical expressions of the linear and third-order nonlinear optical absorption coefficients and refractive index changes are obtained by using the compact-density matrix formalism. Our numerical results show that the optical absorption coefficient and refractive index change are quite sensitive to the applied external fields, such as non resonant intense laser field, electric and magnetic fields. The obtained results can be applied for the design of various optoelectronic devices based on the intersubband transitions of electrons.

WOS: 000292513700010, In this work are studied the intense laser effects on the impurity states in GaAs-Ga1- (x) Al (x) As quantum wells under applied electric and magnetic fields. The electric field is taken oriented along the growth direction of the quantum well whereas the magnetic field is considered to be in-plane. The calculations are made within the effective mass and parabolic band approximations. The intense laser effects have been included through the Floquet method by modifying the confinement potential associated to the heterostructure. The results are presented for several configurations of the dimensions of the quantum well, the position of the impurity atom, the applied electric and magnetic fields, and the incident intense laser radiation. The results suggest that for fixed geometry setups in the system, the binding energy is a decreasing function of the electric field intensity while a dual monotonic behavior is detected when it varies with the magnitude of an applied magnetic field, according to the intensity of the laser field radiation., COLCIENCIAS; CODI-Universidad de Antioquia (Estrategia de Sostenibilidad Grupo de Materia Condensada-UdeA); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia; El Patrimonio Autonomo Fondo Nacional de Financiamiento para la Ciencia, la Technologia y la Innovacion Francisco Jose de Caldas [275-2011]; Mexican CONACYT [CB-2008/101777]; CONACYT; The Scientific and Technological Research Council of Turkey (TUBITAK) [TUBITAK 109T650], This research was partially supported by Colombian Agencies: COLCIENCIAS, CODI-Universidad de Antioquia (Estrategia de Sostenibilidad Grupo de Materia Condensada-UdeA, 2009-2010, 2010-2011), Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2010-2011), and by "El Patrimonio Autonomo Fondo Nacional de Financiamiento para la Ciencia, la Technologia y la Innovacion Francisco Jose de Caldas" Contract RC - No. 275-2011. The work was developed with the help of CENAPAD-SP, Brazil. MEMR acknowledges support from Mexican CONACYT through research grant CB-2008/101777. CAD and MEMR are indebted to COLCIENCIAS and CONACYT for support under the bilateral project "Estudio de propiedades opticas y electronicas en nanoestructuras y sistemas semi-conductores de baja dimension". The authors are grateful to The Scientific and Technological Research Council of Turkey (TUBITAK) for a research grant (TUBITAK 109T650).

WOS: 000285408700084, In this work the effects of intense laser on the electron-related nonlinear optical absorption and nonlinear optical rectification in GaAs-Ga(1-x)Al(x)As quantum wells are studied under, applied electric and magnetic field. The electric field is applied along the growth direction of the quantum well whereas the magnetic field has been considered to be in-plane. The calculations were performed within the density matrix formalism with the use of the effective mass and parabolic band approximations. The intense laser effects are included through the Floquet method, by modifying the confining potential associated to the heterostructure. Results are presented for the nonlinear optical absorption, the nonlinear optical rectification and the resonant peak of these two optical processes. Several configurations of the dimensions of the quantum well, the applied electric and magnetic fields, and the incident intense laser radiation have been considered. The outcome of the calculation suggests that the nonlinear optical absorption and optical rectification are non-monotonic functions of the dimensions of the heterostructure and of the external perturbations considered in this work. (C) 2010 Elsevier B.V. All rights reserved., Colombian Agency: COLCIENCIAS; Colombian Agency: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad Grupo de Materia Condensada-UdeA); Colombian Agency: Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia; Colombian Agency: Excellence Center for Novel Materials/COLCIENCIAS [043-2005]; The Scientific and Technological Research Council of Turkey (TUBITAK) [TUBITAK 109T650], This research was partially supported by Colombian Agencies: COLCIENCIAS, CODI-Universidad de Antioquia (Estrategia de Sostenibilidad Grupo de Materia Condensada-UdeA, 2010-2011), Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2010-2011), and the Excellence Center for Novel Materials/COLCIENCIAS (Contract No. 043-2005). The authors are grateful to The Scientific and Technological Research Council of Turkey (TUBITAK) for a research grant (TUBITAK 109T650). CAD is grateful to Dr. Anna Kurczynska for useful discussions and the critical reading of the manuscript.

The binding energy and diamagnetic susceptibility of a hydrogenic donor in a GaxIn1−xNyAs1−y/GaAs quantum well has investigated in the presence of the magnetic field by using a trial wave function in the framework of the effective mass approximation. The results show that the diamagnetic susceptibility and binding energy of the donor in the GaxIn1−xNyAs1−y/GaAs quantum well increases with nitrogen mole fraction. Also, we concluded that the incorporation of several percent of nitrogen in GaxIn1−xAs alloy causes a larger band gap difference between the well and barrier and therefore deeper quantum well, resulting in the stronger confinement of the donor electron and hence the smaller separation between the electron and impurity atom.

WOS: 000261795700028, The combined effects of hydrostatic pressure and temperature on donor impurity binding energy in GaAs/Ga0.7Al0.3As double quantum well in the presence of the electric and magnetic fields which are applied along the growth direction have been studied by using a variational technique within the effective-mass approximation. The results show that an increment in temperature results in a decrement in donor impurity binding energy while an increment in the pressure for the same temperature enhances the binding energy and the pressure effects on donor binding energy are lower than those due to the magnetic field. (C) 2008 Elsevier B.V. All rights reserved.

WOS: 000381593900018, In the present study, the effects of electric and magnetic fields on the linear and third-order nonlinear optical absorption coefficients and relative change of the refractive index in asymmetric GaAs/GaAlAs double quantum wells under intense laser fields are theoretically investigated. The electric field is oriented along the growth direction of the heterostructure while the magnetic field is taken in-plane. The intense laser field is linear polarization along the growth direction. Our calculations are made using the effective-mass approximation and the compact density-matrix approach. Intense laser effects on the system are investigated with the use of the Floquet method with the consequent change in the confinement potential of heterostructures. Our results show that the increase of the electric and magnetic fields blue-shifts the peak positions of the total absorption coefficient and of the total refractive index while the increase of the intense laser field firstly blue-shifts the peak positions and later results in their red-shifting. (C) 2016 Elsevier B.V. All rights reserved., Scientific Research Project Fund of Cumhuriyet University [TEKNO-007]; project EIA-UdeA ("Efectos de laser intenso sobre las propiedades opticas de nanoestructuras semiconductoras de InGaAsN/GaAs y GaAlAs/GaAs.") Escuela de Ingenieria de Antioquia., The authors are grateful to The Scientific Research Project Fund of Cumhuriyet University under the project number TEKNO-007. CAD is grateful to the Colombian Agencies CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia and projects: "On the way to development of new concept of nanostructure-based THz laser" and "Propiedades opticas de impurezas, excitones y moleculas en puntos cuanticos autoensamblados"), Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication projects 2015-2016); and El Patrimonio Autonomo Fondo Nacional de Financiamiento para la Ciencia, la Tecnologia y la Innovacion, Francisco Jose de Caldas. Co-funded project EIA-UdeA ("Efectos de laser intenso sobre las propiedades opticas de nanoestructuras semiconductoras de InGaAsN/GaAs y GaAlAs/GaAs.") Escuela de Ingenieria de Antioquia.

WOS: 000377228700010, In this work, we investigate the intersubband optical absorption coefficients and refractive index changes for transitions between the lower-lying electronic levels of double quantum wires formed by a symmetric, double quartic-well potential. The system is subjected to an external in-plane magnetic field and Rashba and Dresselhaus spin-orbit couplings are taken into account. The analytical expressions of the linear and nonlinear absorption coefficients and refractive index changes are obtained by using the compact density-matrix approach and iterative method. The dependence of the optical characteristics on the magnetic field, spin-orbit interactions, quantum wire radius, structural parameter and photon energies has been examined. Numerical results exhibit that the optical properties are considerably sensitive to the strength and orientation of magnetic field as well as to the spin-orbit couplings and thus can be controlled by these parameters. (C) 2016 Elsevier B.V. All rights reserved., Scientific and Technological Research Council of Turkey (TUBITAK BiDEB) [2211], The authors B. Gisi and Y. Karaaslan would like to thank the Scientific and Technological Research Council of Turkey (TUBITAK BiDEB 2211) for doctoral scholarship.

WOS: 000251697900012, We have investigated the effects of the magnetic field which is applied perpendicular to the growth direction of the well on the interband absorption and on the binding energy of the excitons in an GaAs/Ga1-xAlxAs inverse parabolic quantum well (IPQW) with different widths as well as different Al concentrations at the well center. The calculations were performed within the effective mass approximation, using a variational method. We observe that IPQW structure turns into parabolic quantum well with the inversion effect of the magnetic field and the effective band gap of the system can be modified by changing Al concentration at the well center, the strength of the magnetic field and well dimensions. This case directly influences the nature of electronic and optical properties in this structure. (c) 2007 Elsevier B.V. All rights reserved.

WOS: 000362603100020, In this work, we studied the effects of in-plane magnetic field and Rashba spin-orbit interaction on the intersubband optical absorption coefficients and changes in refractive index for transitions between the first two lower-lying electronic levels of quantum wire represented by a parabolic confining potential. The analytical expressions of the linear and third-order nonlinear optical absorption coefficients and refractive index changes are obtained by using the compact-density matrix formalism and iterative scheme. Optical properties are investigated as a function of quantum wire radius, strength and orientation of magnetic field, strength of Rashba spin-orbit interaction and photon energies. Numerical results reveal that the optical absorption coefficients and refractive index changes are strongly affected and thus can be controlled by these parameters. (C) 2015 Elsevier Ltd. All rights reserved., Scientific and Technological Research Council of Turkey [TUBITAK BIDEB 2211], One of the authors (B. Gisi) would like to thank the Scientific and Technological Research Council of Turkey (TUBITAK BIDEB 2211) for partial financial support.

WOS: 000235860200017, The binding energy of the donor in the triple-graded GaAs-(Ga,Al)As quantum well under the hydrostatic pressure, electric and magnetic fields are calculated by using a variational approach. The results have been obtained in the presence of hydrostatic pressure, magnetic and electric fields applied along the growth direction as a function of the impurity position without consideration of a mass mismatch or dielectric mismatch. (c) 2005 Elsevier B.V. All rights reserved.

WOS: 000186497100020, By using an appropriate coordinate transformation, we have calculated variationally the ground state binding energy of a hydrogenic donor impurity in a quantum well in the presence of crossed electric and magnetic fields which are applied tilted at an angle to the layers. The dependence of the donor impurity binding energy on the well width, on the strength of the electric and magnetic fields, on the impurity position and on the directions of the external fields is discussed.

WOS: 000346845200030, This paper presents the results of the theoretical study of the effects of non resonant intense laser field and electric and magnetic fields on the optical properties (the linear and third order nonlinear refractive index and absorption coefficients) in an asymmetric quantum well. The electric field and intense laser field are applied along the growth direction of the asymmetric quantum well and the magnetic field is oriented perpendicularly. To calculate the energy and the wave functions of the electron in the asymmetric quantum well, the effective mass approximation and the method of envelope wave function are used. The asymmetric quantum well is constructed by using different aluminium concentrations in both right and left barriers. The confinement in the quantum well is changed drastically by either the effect of electric and magnetic fields or by the application of intense laser field. The optical properties are calculated using the compact density matrix approach. The results show that the effect of the intense laser field competes with the effects of the electric and magnetic fields. Consequently, peak position shifts to lower photon energies due to the effect of the intense laser field and it shifts to higher photon energies by the effects of electric and magnetic fields. In general, it is found that the concentration of aluminum, electric and magnetic fields and intense laser field are external agents that modify the optical responses in the asymmetric quantum well. (C) 2014 Elsevier B.V. All tights reserved., Scientific Research Project Fund of Cumhuriyet University [F-399, F-410]; CODI-Universidad de Antioquia; Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia; EL PATRIMONIO AUTONOMO FONDO NACIONAL DE FINANCIAMIENTO PARA LA CIENCIA, LA TECNOLOGIA Y LA INNOVACION, FRANCISCO JOSE DE CALDAS; Mexican CONACYT [CB-2008-101777]; Escuela de lngenieria de Antioquia; EIA-UdeA, The authors are grateful to The Scientific Research Project Fund of Cumhuriyet University under the projects number F-399 and F-410. This research was partially supported by Colombian Agencies: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad 2014-2015 de la Universidad de Antioquia), Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2014-2015), and by EL PATRIMONIO AUTONOMO FONDO NACIONAL DE FINANCIAMIENTO PARA LA CIENCIA, LA TECNOLOGIA Y LA INNOVACION, FRANCISCO JOSE DE CALDAS. MEMR acknowledges support from Mexican CONACYT through Grant CB-2008-101777, The Escuela de lngenieria de Antioquia co-supported EIA-UdeA project: Efectos de laser intenso sobre las propiedades opticas de nanoestrucuras semiconductoras de InGaAsN/GaAs y GaAlAs/GaAs. RLR is also grateful to the Physics Department of the Cumhuriyet University in Sivas-Turkey for the support and hospitality during his research stay.

WOS: 000359873200042, We investigate the effects of Rashba spin-orbit interaction on the electronic energy dispersion and zero-temperature ballistic conductance of double quantum wire under the influence,of perpendicular magnetic field. The wire system is represented by a symmetric, double quartic-well confinement potential. Numerical results reveal that competing effects between spin-orbit interaction and magnetic field modify strongly the energy subband structure and introduce anticrossings between subbands. Moreover, it is found that the conductance character of a quasi-one-dimensional ballistic conductor, which is closely related to the energy-dispersion spectrum, is very sensitive to the shape of potential profile, magnetic field and Rashba spin-orbit coupling. (C) 2015 Elsevier Ltd. All rights reserved., Scientific and Technological Research Council of Turkey [TUBITAK BIDEB 2211], One of the authors (Y. Karaaslan) would like to thank the Scientific and Technological Research Council of Turkey (TUBITAK BIDEB 2211) for partial financial support. This work has been completed at the Dokuz Eylul University, Graduate School of Natural and Applied Sciences and is the subject of the forthcoming Ph.D. Thesis of Yenal Karaaslan.

WOS: 000366876100025, This paper presents the results of the theoretical study of the effects of non-resonant intense laser field and electric and magnetic fields on the optical properties in an quantum well (QW) make with Woods Saxon potential profile. The electric field and intense laser field are applied along the growth direction of the Woods Saxon quantum well and the magnetic field is oriented perpendicularly. To calculate the energy and the wave functions of the electron in the Woods Saxon quantum well, the effective mass approximation and the method of envelope wave function are used. The confinement in the Woods Saxon quantum well is changed drastically by the application of intense laser field or either the effect of electric and magnetic fields. The optical properties are calculated using the compact density matrix. (C) 2015 Elsevier Ltd. All rights reserved., Escuela de Ingenieria de Antioquia co; Colombian Agencies: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project); PATRIMONIO AUTONOMO FONDO NACIONAL DE FINANCIAMIENTO PARA LA CIENCIA, LA TECNOLOGIA Y LA INNOVACION, FRANCISCO JOSE DE CALDAS, The Escuela de Ingenieria de Antioquia co-supported EIA-UdeA project: Efectos de laser intenso sobre las propiedades opticas de nanoestrucuras semiconductoras de InGaAsN/GaAs y GaAlAs/GaAs. This research was partially supported by Colombian Agencies: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad 2014-2015 de la Universidad de Antioquia), Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2014-2015), and by EL PATRIMONIO AUTONOMO FONDO NACIONAL DE FINANCIAMIENTO PARA LA CIENCIA, LA TECNOLOGIA Y LA INNOVACION, FRANCISCO JOSE DE CALDAS.

WOS: 000350075500023, In the present work, the effects of the intense laser field on total optical absorption coefficient (the linear and third-order nonlinear) and total refractive index change for transition between two lower-lying electronic levels in the step-like GaAs/Ga1-xAlxAs quantum well under external electric and magnetic fields are investigated. The calculations were performed within the compact density-matrix formalism with the use of the effective mass and parabolic band approximations. The obtained results show that both total absorption coefficient and refractive index change are sensitive to the well dimensions and the effects of external fields. By changing the intensities of the electric, magnetic and non-resonant intense laser fields together with the well dimensions, we can obtain the blue or red shift, without the need for the growth of many different samples. (C) 2015 Elsevier B.V. All rights reserved., Cumhuriyet University [F-410]; Colombian Agencies: CODI-Universidad de Antioquia. (Estrategia de Sostenibilidad de la Universidad de Antioquia); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia(CAD-exclusive dedication project); EL PATRIMONIO AUTONOMO FONDO NACIONAL DE FINANCIAMIENTO PARA LA CIENCIA; LA TECNOLOGIA Y LA INNOVACION, FRANCISCO JOSE DE CALDAS; Mexican CONACYT [CB-2008-101777]; EIA-UdeA project: Efectos de laser intenso sobre las propiedades opticas de nanoestrucuras semiconductoras de InGaAsN/GaAs y GaAlAs/GaAs; Physics Depai linent of the Cumhuriyet University in Sivas, Turkey, The authors are grateful to The Scientific Research Project Fund of Cumhuriyet University under the project number F-410. This research was partially supported by Colombian Agencies: CODI-Universidad de Antioquia. (Estrategia de Sostenibilidad 2014-2015 de la Universidad de Antioquia), Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia(CAD-exclusive dedication project 2014-2015), and by EL PATRIMONIO AUTONOMO FONDO NACIONAL DE FINANCIAMIENTO PARA LA CIENCIA, LA TECNOLOGIA Y LA INNOVACION, FRANCISCO JOSE DE CALDAS. MEMR acknowledges support from Mexican CONACYT through Grant CB-2008-101777. The Escuela de Ingenieria de Antioquia co-supported EIA-UdeA project: Efectos de laser intenso sobre las propiedades opticas de nanoestrucuras semiconductoras de InGaAsN/GaAs y GaAlAs/GaAs. RLR is also grateful to the Physics Depai linent of the Cumhuriyet University in Sivas, Turkey for the support and hospitality during his research stay.

WOS: 000085453200026, The binding energy of excitons in symmetric and asymmetric coupled double GaAs/Ga1-xAlxAs quantum wells is calculated by using a variational approach. The results have been obtained in the presence of a uniform magnetic field, as a function of the potential symmetry, size of the quantum well and coupling parameter of the wells. We show that by increasing the applied magnetic field one can obtain large binding between electrons and holes which is similar to the change in the dimensions of the structure. This behaviour in the excitonic binding for different wells and barrier geometries can be used to study these systems in regions of interest, without the need for the growth of many different samples.

WOS: 000331026900014, In the present work, the effects of electric and magnetic fields on the optical absorption coefficient and refractive index changes associated with intersubband transitions in a GaAs/AlxGa1-xAs double inverse parabolic quantum well are theoretically calculated within the effective-mass approximation. The expressions for the linear and third-order nonlinear absorption coefficients and refractive index changes are those obtained by using the compact density-matrix approach and iterative method. The results are presented as functions of the incident photon energy for different values of the applied electric and magnetic fields. It is found that the optical absorption coefficient and refractive index changes are strongly affected by the applied electric and magnetic fields. (C) 2013 Elsevier Ltd. All rights reserved., CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication Project); EL PATRIMONIO AUTONOMO FONDO NACIONAL DE FINANCIAMIENTO PARA LA CIENCIA, LA TECNOLOGIA Y LA INNOVACION, FRANCISCO JOSE DE CALDAS; Mexican CONACYT [101777]; Scientific Research Project Fund of Cumhuriyet University [F-399]; Escuela de Ingenieria de Antioquia, This research was partially supported by Colombian Agencies: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad 2013-2014 de la Universidad de Antioquia), Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication Project 2013-2014), and by EL PATRIMONIO AUTONOMO FONDO NACIONAL DE FINANCIAMIENTO PARA LA CIENCIA, LA TECNOLOGIA Y LA INNOVACION, FRANCISCO JOSE DE CALDAS. The Escuela de Ingenieria de Antioquia co-supported EIA-UdeA project: Efectos de laser intenso sobre las propiedades opticas de nanoestrucuras semiconductoras de InGaAsN/GaAs y GaAlAs/GaAs. MEMR acknowledges support from Mexican CONACYT through Grant No. 101777. The authors are grateful to The Scientific Research Project Fund of Cumhuriyet University under the Project Number F-399. The work was done with the help of CENAPAD-SP, Brazil.

WOS: 000340626600016, In the present work, total optical absorption coefficient (the linear and third-order nonlinear) and total refractive index change for transition between two first lower-lying electronic levels in the step-like GaAs/Ga1-xAlxAs quantum well under the electric and magnetic fields are investigated and also the effect of relaxation time on saturation is investigated. A compact density-matrix approach is applied to investigate optical properties. The obtained results show that both total absorption coefficient and refractive index change are sensitive to well dimensions more than external fields. With the increase of quantum well width, total absorption coefficient and refractive index change shift to lower photon energies (red shift), the magnitude of total refractive index increases significantly while total absorption coefficient is reduced. Furthermore, the electric and magnetic fields induce a blue-shift on absorption coefficient and refractive index change. (C) 2014 Elsevier B.V. All rights reserve, CODI-Universidad de Antioquia (Estrategia de Sostenibilidad de la Universidad de Antioquia); Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project); El Patrimonio Autonomo Fondo Nacional de Financiamiento para la Ciencia, la Tecnologia y la Innovacion, Francisco Jose de Caldas; Mexican CONACYT [101777]; Cumhuriyet University [F-399, F-410], This research was partially supported by Colombian Agencies: CODI-Universidad de Antioquia (Estrategia de Sostenibilidad 2013-2014 de la Universidad de Antioquia), Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2013-2014), and by El Patrimonio Autonomo Fondo Nacional de Financiamiento para la Ciencia, la Tecnologia y la Innovacion, Francisco Jose de Caldas. M.E.M.R. acknowledges support from Mexican CONACYT through Grant no. 101777. The authors are grateful to The Scientific Research Project Fund of Cumhuriyet University under the project number F-399 and F-410. The work was done with the help of CENAPAD-SP, Brazil.

WOS: 000319490900011, In this study, the interband optical transitions and the binding energy of an exciton in a GaAs/Ga1-xAlxAs V-shaped quantum well (VQW) under the electric and magnetic fields are calculated. The calculations were performed within the effective mass approximation, using a variational method. It has been observed that the electric and magnetic fields provide an important effect on the electronic and optical properties in the VQW and the changes in the binding energy depend on the shape of the confinement potential. (C) 2013 Elsevier Ltd. All rights reserved.

WOS: 000303297200003, In this present work, we have investigated theoretically the effects of applied electric and magnetic fields on the linear and nonlinear optical properties in a GaAs/AlxGa1-xAs inverse parabolic quantum well for different Al concentrations at the well center. The Al concentration at the barriers was always x(max) = 0.3. The energy levels and wave functions are calculated within the effective mass approximation and the envelope function approach. The analytical expressions of optical properties are obtained by using the compact density-matrix approach. The linear, third-order nonlinear and total absorption and refractive index changes depending on the Al concentration at the well center are investigated as a function of the incident photon energy for the different values of the applied electric and magnetic fields. The results show that the applied electric and magnetic fields have a great effect on these optical quantities. (C) 2012 Elsevier B.V. All rights reserved.

WOS: 000300653200005, In this work we are studying the intense laser effects on the electron-related linear and nonlinear optical properties in GaAs-Ga1-xAlxAs quantum wells under applied electric and magnetic fields. The calculated quantities include linear optical absorption coefficient and relative change of the refractive index, as well as their corresponding third-order nonlinear corrections. The nonlinear optical rectification and the second and third harmonic generation coefficients are also reported. The DC applied electric field is oriented along the hererostructure growth direction whereas the magnetic field is taken in-plane. The calculations make use of the density matrix formalism to express the different orders of the dielectric susceptibility. Additionally, the model includes the effective mass and parabolic band approximations. The intense laser effects upon the system enter through the Floquet method that modifies the confinement potential associated to the heterostructure. The results correspond to several configurations of the dimensions of the quantum well, the applied electric and magnetic fields, and the incident intense laser radiation. They suggest that the nonlinear optical absorption and optical rectification are nonmonotone functions of the dimensions of the heterostructure and of the external perturbations considered in this work. (C) 2011 Elsevier B.V. All rights reserved., CONACYT (Mexico); COLCIEN-CIAS (Colombia); Mexican CONACYT [CB-2008-101777]; Scientific and Technological Research Council of Turkey (TUBITAK) [TUBITAK 109T650], C.A.D. and M.E.M.R. thank CONACYT (Mexico) and COLCIEN-CIAS (Colombia) for support under the 2009-2011 Bilateral Agreement Estudio de los efectos de la presion hidrostatica y la mezcla de estados de conduccion sobre la estructura elect-re:Mica y los estados excitonicos en nanoestructuras basadas en semiconductores III-V. M.E.M.R. also acknowledges support from Mexican CONACYT through Grant CB-2008-101777. C.A.D. is grateful to the Colombian Agencies CODI-Universidad de Antioquia (Estrategia de Sostenibilidad Grupo de Materia Condensada-UdeA, 2011-2012), Facultad de Ciencias Exactas y Naturales-Universidad de Antioquia (CAD-exclusive dedication project 2011-2012), and "El Patrimonio Autonomo Fondo Nacional de Financiamiento para la Ciencia, la Tecnologia y la Innovacion Francisco Jose de Caldas" Contract RC No. 275-2011. The work was developed with the help of CENAPAD-SP, Brazil. The authors are grateful to The Scientific and Technological Research Council of Turkey (TUBITAK) for a research Grant (TUBITAK 109T650).

WOS: 000296781800005, The intersubband transitions and impurity binding energy in differently shaped semiconductor quantum wells under a magnetic field are calculated using a variational method within the effective mass approximation. Our calculations have revealed the dependence of the intersubband transitions and impurity binding energy on the magnetic field strength and the shape of the quantum wells.

WOS: 000255159700001, The binding energy of a hydrogen-like impurity in an ellipsoidal parabolic quantum dot under the magnetic and electric fields have been discussed by using the effective mass approximation and the variational method. We have calculated the effects of the magnetic and electric fields on the binding energy of donor impurities in the quantum dots with different confinement potentials. We conclude that the structural confinement is very effective, and especially in the weak confinement potential case the magnetic field dependence of the donor binding energy is more pronounced.

WOS: 000245484200034, We investigated the effects of the magnetic field on the density of impurity states in a GaAs/GaAlAs inverse parabolic quantum well (lPQW) for different Al concentrations at the well center. The calculations were performed within the effective mass approximation, using a variational method. We report in this paper the effects of the magnetic field, well width and the Al concentration at the well center on the density of states and the binding energies of the donor impurities. (c) 2006 Elsevier B.V. All rights reserved.

WOS: 000244210400036, We have investigated the effects of the magnetic field which is directed perpendicular to the well on the binding energy of the hydrogenic impurities in an inverse parabolic quantum well (IPQW) with different widths as well as different Al concentrations at the well center. The Al concentration at the barriers was always x(max) = 0.3. The calculations were performed within the effective mass approximation, using a variational method. We observe that IPQW structure turns into parabolic quantum well with the inversion effect of the magnetic field and donor impurity binding energy in IPQW strongly depends on the magnetic field, Al concentration at the well center and well dimensions. (c) 2006 Elsevier B.V. All rights reserved.

International Conference on Superlattices, Nano-Structures and Nano-Devices -- JUL 30-AUG 04, 2006 -- Istanbul, TURKEY, WOS: 000245877200029, In this study, we have calculated the donor impurity binding energy, donor impurity related photoionization cross-section and polarizability in symmetric GaAs/Ga1-xAlxAs quantum well-wire as a function of the impurity positions, dimensions of the structures and external electric and magnetic field, the calculations were performed within the effective mass approximation, using a variational method.

WOS: 000244516800008, The binding energy of the donor in three different shaped triple graded GaAs-(Ga, Al)As quantum wells which is obtained by changing the depth of the central-well potential (V-o) is calculated by using a variational approach. The results have been obtained in the presence of uniform magnetic and electric fields applied along the growth direction as a function of the impurity position. In addition, we also give the binding energy of the hydrogenic donor impurity for triple square quantum wells having the same physical parameters with triple graded quantum well structures in order to see the effect of different geometric confinements on the donor impurity binding energy.

WOS: 000227813200026, We have calculated variationally the ground state binding energy of a hydrogenic donor impurity in V-shaped quantum well (VQW) or full-graded GaAs/Ga1-xAlxAs quantum wells in the presence of crossed electric and magnetic fields. These homogeneous crossed fields are such that the magnetic field is parallel to the heterostructure layers and the electric field is applied perpendicular to the magnetic field. The dependence of the donor impurity binding energy on the well width and the strength of the electric and magnetic fields are discussed. We hope that obtained results will provide important improvements in device applications, especially for narrow well widths and for a suitable choice of both fields. (c) 2004 Elsevier B.V. All rights reserved.

WOS: 000225782500050, We have calculated variationally the ground state binding energy of a hydrogenic donor impurity in a parabolic quantum well in the presence of crossed electric and magnetic fields. These homogeneous crossed fields are such that the magnetic field is parallel to the heterostructure layers and the electric held is applied perpendicular to the magnetic field. The dependence of the donor impurity binding energy to the well width and the strength of the electric and magnetic fields are discussed. We hope that the obtained results will provide important improvements in device applications, especially for a suitable choice of both fields in the narrow well widths.