Linear and nonlinear absorption coefficients of spherical quantum dot inside external magnetic field

WOS: 000398056700013We have calculated the wavefunctions and energy eigenvalues of spherical quantum dot with infinite potential barrier inside uniform magnetic field. In addition, we have investigated the magnetic field effect on optical transitions between Zeeman energy states. The results are expressed as a function of dot radius, incident photon energy and magnetic field strength. The results present that, in large dot radii, the external magnetic field affects strongly the optical transitions between Zeeman states. In the strong spatial confinement case, energy level is relatively insensitive to the magnetic field, and electron spatial confinement prevails over magnetic confinement. Also, while m varies from -1 to +1, the peak positions of the optical transitions shift toward higher energy (blueshift).Research Fund of the Aksaray University [2016-048]; Selcuk University BAP officeThis work has been supported by Research Fund of the Aksaray University. Project no.: 2016-048. And also, it has been partially supported by Selcuk University BAP office

Refractive index changes and absorption coefficients in a spherical quantum dot with parabolic potential

WOS: 000306876000028In this study, we have calculated the linear, nonlinear and total refractive index changes and absorption coefficients for the transitions 1s-1p, 1p-1d and 1d-1f in a spherical quantum dot with parabolic potential. Quantum Genetic Algorithm (QGA) and Hartree-Fock-Roothaan (HFR) method have been employed to calculate the wavefuctions and energy eigenvalues. The results show that impurity, dot radius, stoichiometric ratio, incident optical intensity and carrier density of the system have important effects on the optical refractive index changes and absorption coefficients. Also, we find that as the transitions between orbitals with big I value move to lower energy region in case with parabolic potential, in case without parabolic potential these transitions move to higher energy region.Selcuk University BAP officeThis work is partially supported by Selcuk University BAP office

Computation of relativistic terms in a spherical quantum dot

WOS: 000313393300122We studied a hydrogenic impurity located at the center of a spherical quantum dot with an infinite spherical confining potential and calculated energy levels and wavefunctions using Quantum Genetic Algorithm(QGA) and Hartree-Fock Roothaan (HFR) method. In addition, we investigated the first-order relativistic terms such as the relativistic correction to the kinetic energy, Darwin and spin-orbit interaction term. These terms were calculated using the first-order perturbation theory. The electronic charge density for the Darwin term was carried out from a global operator defined by Hiller, Sucher and Feinberg. The results revealed that the relativistic corrections are important in small dot radii and they should not be neglected to improve the accuracy of calculations. Crown CopyrightSelcuk University BAP OfficeThis work is partially supported by Selcuk University BAP Office

Linear and nonlinear optical properties in spherical quantum dots

WOS: 000278904200039We calculate the energy eigenvalues and the sate functions of one-electron Quantum Dot (QD) by using a combination of Quantum Genetic Algorithm (QGA) and Hartree-Fock-Roothaan (HFR) method. The linear and the third-order nonlinear optical absorption coefficients for the 1s-1p, 1p-1d, and 1d-1f transitions are examined as a function of the incident photon energy for three different values of the stoichiometric ratio. The results show that the stoichiometric ratio, impurity, relaxation time, and dot size have great influence on the optical absorption coefficients of QDs.Selcuk University BAP OfficeThis Work is Partially Supported by Selcuk University BAP Offic

Dipole and quadrupole polarizabilities and oscillator strengths of spherical quantum dot

WOS: 000444622300033In this study, the energy eigenvalues and eigenfunctions of the ground and excited states of a spherical quantum dot are calculated by using the Quantum Genetic algorithm (QGA) and Hartree-Eock Roothaan (HFR) method. Based on the calculated energies and wave functions, the static and dynamic dipole polarizabilities, the quadrupole polarizability, dipole and quadrupole oscillator strengths of spherical quantum dot are carried out as a function of dot size and the confining potential as perturbative. The results show that dot size and confining potential have a great influence on the polarizability and oscillator strength. It is found that the polarizability increases due to the spatial confinement effect in the strong confinement region. In the weak confinement region, the polarizability increases again until it reaches the saturation value. In addition, the peak positions of the dipole and quadrupole oscillator strengths shift toward smaller dot radii with the increases of the potential well depth.Research Fund of Aksaray University [2017-028]; Selcuk University BAP officeThis work has been supported by Research Fund of Aksaray University-Project Number: 2017-028. And also, it has been partially supported by Selcuk University BAP office

Calculation of oscillator strength and the effects of electric field on energy states, static and dynamic polarizabilities of the confined hydrogen atom

In this study, we investigate the effect of an electric field on energy states of a spherical quantum dot with infinite confining potential using the perturbation method. We also perform the static dipole and dynamic dipole polarizabilities. In addition, the oscillator strengths have been calculated for the dipole transitions between higher unperturbed states. The results show that impurity and dot radius have an important effect on the Stark shift, and the effect of electric field is insensitive in small dot radii. For the excited states the Stark shift from the first-order increases linearly with the increase of electric field strength. On the other hand, the Stark shift from the first-order decreases with increasing of the magnetic quantum number. A very important future is that, for dot radius region 1.8aB?R?7 aB, the static dipole polarizabilities change very quickly. In addition, it is found that as the dot radius increases, the photon energy corresponding to the singularity of dynamic dipole polarizability decreases. © 2013 Elsevier B.V.This work is partially supported by Selçuk University BAP Office

Magnetic field effects on oscillator strength, dipole polarizability and refractive index changes in spherical quantum dot

WOS: 000443278800024We have computed the ground and excited state energies and the wave functions of a spherical quantum dot with finite potential barrier in the presence of magnetic field. The oscillator strength, the static dipole polarizability and the refractive index changes are investigated as a function of dot radius and magnetic field strength. The results show that the energy state, the oscillator strength, the static dipole polarizability and the refractive index changes are strongly affected by the magnetic field strength and dot size. It is found that while the magnetic field strength increases, the static polarizability decreases strongly.Research Fund of Aksaray University [2017-028]; Selcuk University BAP officeThis work has been supported by Research Fund of Aksaray University - Project Number: 2017-028. And also, it has been partially supported by Selcuk University BAP office

Linear and nonlinear optical absorption coefficients of two-electron spherical quantum dot with parabolic potential

WOS: 000346845300023Linear and nonlinear absorption coefficients of two electron spherical quantum clot (QD) with parabolic potential are investigated in this paper. Wave functions and energy eigenvalues of the 1s(2), 1s1p, 1s1d and 1s1f electronic states have been computed by using an optimization approach, which is a combination of Quantum Genetic Algorithm (QGA) and Hartree-Fock Roothaan (I-IFR) method. It is found that the strength of S -> P transition is stronger than P -> D and D -> F transitions. Also the peak positions and amplitudes of the absorption coefficients are sensitive to the electron spin. It should be noted that the peak positions and amplitudes of absorption coefficients are strongly dependent on the parabolic potential. Additionally, dot radius, impurity charge, incident optical intensity and relaxation time have a great influence on the linear and nonlinear absorption coefficients.Selcuk University BAP officeThis work is partially supported by Selcuk University BAP office

Linear and nonlinear absorption coefficients of spherical two-electron quantum dot

WOS: 000348261300010In this study, optical properties of two-electron quantum dot confined by an infinite spherical potential surface have been investigated. Linear, nonlinear and total absorption coefficients of S -> P, P -> D and D -> F dipole-allowed transitions between singlet-singlet and triplet-triplet states have been calculated as a function of dot radius and photon energy. The results show that the change of dot radius and incident optical intensity effects the peak positions and amplitudes of linear and nonlinear absorption coefficients. Besides, it has been found that the absorption coefficients of transitions between triplet states are stronger than those of the singlet states, and also triplet absorption transitions occur at higher energies.Selcuk University BAP officeThis work is partially supported by Selcuk University BAP office