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Öğe Donor impurity atom effect on the inter-subband absorption coefficient for symmetric double n-type ?-doped GaAs quantum well(Academic Press Ltd- Elsevier Science Ltd, 2021) Rodriguez-Magdaleno, K. A.; Turkoglu, A.; Ungan, F.; Mora-Ramos, M. E.; Martinez-Orozco, J. C.In this work, the electronic structure and the inter-subband absorption coefficient (IAC) are theoretically studied for symmetric double n-type delta-doped GaAs quantum well considering the donor impurity atom effect. The electron states are determined by a diagonalization procedure, working within the effective mass and parabolic band approximations, and the effect of donor center is treated via the variational method. Meanwhile, linear and nonlinear contributions for the inter-subband absorption coefficient were evaluated from expressions usually derived within the perturbative solution of the Von Neumann equation for density matrix. We report the impurity binding energy by considering a donor atom located at the center of the system (at z(i) = 0). We found that the reported physical properties become more sensitive to the inter-well separation distance L-w than to the delta-doping density, N-2d. In the former case the total optical absorption coefficient undergoes an important red-shift as well as a significant decrease in its magnitude. When N-2d values increase, the binding energy exhibits a contrary effect, and the total optical absorption coefficient exhibits an small blue-shift with no significant changes in its magnitude. The presence of the donor impurity atom in the system represents one factor that can modify the location of inter-subband absorption coefficient, by inducing a blue-shift of the optical response. The resonant peak energies are within the range of several terahertz, showing potential device applications within this range of the electromagnetic spectrum.Öğe Effect of exchange-correlation potential on the plasmon dispersions in a doped symmetrical double quantum well(WILEY-V C H VERLAG GMBH, 2007) Tuezemen, E. Senadim; Turkoglu, A.; Ergun, Y.; Sokmen, I.; Tanatar, B.We have calculated the plasmon dispersion relations in a doped double quantum well with and without exchange-correlation potential added to the effective potential of the system. The calculations were done for high and low doping densities by solving the Schrodinger and Poisson equations self-consistently. Our numerical results show that the exchange - correlation potential is quite important at high doping densities of donor impurities for plasmon dispersions at large wave vectors. On the other hand, the ratio of subband populations n(i) to donor density N-D is more affected at low densities. (C) 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.Öğe Non-resonant intense laser field effect on the nonlinear optical properties associated to the inter- and intra-band transitions in an anharmonic quantum well submitted to electric and magnetic field(Pergamon-Elsevier Science Ltd, 2021) Turkoglu, A.; Aghoutane, N.; Feddi, E.; Mora-Ramos, M. E.; Ungan, F.Simultaneous effects of electric, magnetic, and non-resonant intense laser field on the nonlinear optical properties of a GaAs quantum well with an anharmonic confinement potential profile are theoretically investigated. Energy eigenvalues and eigenfunctions of the system are determined using the diagonalization method within the framework of the effective mass and parabolic band approximation. Nonlinear optical properties associated to the inter and intra band transitions are evaluated. Our numerical results for the intraband response show that the resonance peak positions of the total optical absorption coefficients and relative refractive index changes shift towards higher energy levels (blueshift) by increasing the strength of the applied external electric, magnetic, and non-resonant intense laser field. The analysis of inter-band (electron-heavy hole) transitions reveals that the optical coefficients has a pronounced redshift induced by the electric field while a blueshift is caused by the magnetic and laser signals. It is seen that the nonlinear optical properties of such structures can be adjusted according to the purpose by changing the external perturbations and could be used in new optoelectronic device designs.Öğe Nonlinear optical properties of a quantum well with inversely quadratic Hellman potential(Springer Science and Business Media Deutschland GmbH, 2021) Turkoglu, A.; Dakhlaoui, H.; Durmuslar, A. Salman; Mora-Ramos, M.E.; Ungan, F.Abstract: A theoretical investigation of intraband nonlinear optical properties of a GaAs quantum well with inversely quadratic Hellman potential have been performed. It considers the presence of external electric and magnetic fields. In addition to this, the effects of the adjustable physical parameters (? and V) of the system on the optical properties of this structure were also investigated. For these numerical calculations, firstly, the conduction subband energy levels and the corresponding wave functions are obtained by solving the Schrödinger equation using the diagonalization method within the framework of effective mass and parabolic band approximations. Based on this information, results of numerical calculations for the linear, third-order nonlinear, and total optical absorption and relative refractive index change coefficients are presented. The obtained numerical results show the increase of the resonance peaks amplitudes with applied external electric and magnetic fields, as well as the shifting of their position the towards higher energies. It was also observed that the variations in ? and V have important effects on the magnitude and position of the resonance peaks. We believe that these results can be helpful in the design and practice of the optoelectronic devices used in the terahertz electromagnetic spectrum. Graphic abstract: [Figure not available: see fulltext.] © 2021, The Author(s), under exclusive licence to EDP Sciences, SIF and Springer-Verlag GmbH Germany, part of Springer Nature.Öğe The non-resonant intense laser field effects on the binding energies and the nonlinear optical properties of a donor impurity in Rosen-Morse quantum well(Indian Assoc Cultivation Science, 2022) Durmuslar, A. Salman; Turkoglu, A.; Mora-Ramos, M. E.; Ungan, F.We analyze the influence of electron-donor impurity interaction as well as of a high-frequency non-resonant intense laser field on the intraband linear, third-order nonlinear, and total optical absorption coefficients in a GaAs/GaAlAs heterostructure with conduction band Rosen-Morse potential profile. For this, firstly, the binding energies associated with ground and first excited states (1s, 2s) of a hydrogenic donor center have been calculated as functions of the impurity position using the effective-mass approximation and a variational procedure. Then, the linear, third-order nonlinear, and total optical absorption coefficients were evaluated for transitions between the impurity and subband electronic states. Emphasis is made on understanding the role of structure parameters on the features of these nonlinear optical properties. The numerical results show that the impurity binding energies and lowest intersubband transitions depend strongly on the high-frequency intense laser field. The presence of impurity atom causes a blueshift in the optical spectrum and an increase in the amplitude of absorption coefficients. Additionally, it was observed that studied optical transitions are sensitive to the structure parameters and high-frequency intense laser field, thus affecting the optical absorption response.
