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1.
The spectral dependence of the photoionization cross-section is calculated for shallow donors in GaAs/GaAlAs heterojunctions. The resulting spectra is found to be different for light polarized along and perpendicular to the growth direction. The calculations are repeated for both infinite- and finite-barrier models. 相似文献
2.
A. Biber A. Golick M. Tomak 《International Journal of Infrared and Millimeter Waves》2002,23(9):1315-1325
This paper presents the analytical proof of Time-Domain Mapping Method for the spherical resonator made up of uniaxial crystal. In this way, the main types of caustics inside the spherical resonator made up of uniaxial crystal, which were investigated numerically before, are confirmed analytically. It is engraved that the problem of the ray flow inside the spherical resonator can be reduced to the problem of the ray flow inside metal cavity shaped as spheroid. 相似文献
3.
İ. Karabulut Ü. Atav H. Şafak M. Tomak 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,55(3):283-288
The linear and nonlinear intersubband optical absorptions
in AlxlGa1-xlAs/GaAs/Alxr Ga1-xrAs asymmetric rectangular
quantum well are studied within the framework of the density matrix
formalism. We have calculated the electron energy levels and the envelope
wave functions using the effective mass approach. In addition, we have
obtained an expression for saturation intensity. It is shown that the
parameters such as asymmetry and width of potential well not only shift the
peak positions in absorption spectrum but also considerably modify their
height. These results suggest that the absorption process can be easily
controlled by the structure parameters of an asymmetric rectangular quantum
well. Also, the incident optical intensity has a great effect on the total
absorption spectrum. We have seen that the absorption peak is reduced by
half when the optical intensity is approximately 0.8 MW/cm2 for well
width L=90 ? and β=0.5. Moreover, it is seen that the
saturation intensity is quite sensitive to the structure parameters of an
asymmetric rectangular quantum well. Thus, the results presented here can be
useful for electro-optical modulators and photodetectors in the infrared
region. 相似文献
4.
O. Üzengi Aktürk E. Aktürk M. Tomak 《International Journal of Theoretical Physics》2008,47(12):3310-3320
In this paper, we focus on Sobolev inequality in the context of Sharma-Mittal entropy. Using this new inequality, generalized entropic uncertainty relation in accordance with Sharma-Mittal entropy is derived and the pseudoadditivity relation has been obtained. This new entropic uncertainty relation has then been applied to physical examples such as one dimensional harmonic oscillator and Pösch-Teller potential. Finally, it has been shown that for certain values of the parameters of Sharma-Mittal measure, the present results reduce to the corresponding results of Shannon, Renyi and Tsallis measures. 相似文献
5.
This paper describes potential applications of multi-attribute preference models (MAPM) in e-commerce and offers some guidelines for their implementation. MAPM are methodologies for modeling complex preferences that depend on more than one attribute or criterion, and include multi-attribute utility theory, conjoint analysis, and the Analytic Hierarchy Process. There are numerous examples of applications in e-commerce that would benefit from the acquisition of information regarding the preferences of a consumer, a customer, an advice seeker, or a decision maker. Here, the focus is on applications of MAPM models in B2C and B2B websites, where preferences of consumers are assessed for the purpose of identifying products or services that closely match their needs. 相似文献
6.
Ertan?Aksahin Vildan?Ustoglu UnalEmail author Mehmet?Tomak 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(11):265
An exciton in a spherical quantum dot is studied analytically within the effective mass approximation. A parabolic confinement under an electric field is considered. The linear and nonlinear optical absorption coefficients are calculated within the density matrix formalism. No assumptions are made about the strength of the confinement. It is shown how the competing mechanisms of the Coulomb interaction, the confinement and the applied static electric field affect the optical absorption. 相似文献
7.
Il Nuovo Cimento D - The electrical resistivity of liquid Al−Mg and Al−Cu alloys is calculated using both the Faber-Ziman and «2k F» scattering theories. The partial structure... 相似文献
8.
The charge density and pair correlation function of three interacting electrons confined within a two-dimensional disc-like hard-wall quantum dot are calculated by full numerical diagonalization of the Hamiltonian. The formation of a Wigner molecule in the form of equilateral triangular configuration for electrons is observed as the size of the dot is increased. 相似文献
9.
H. Yildirim M. Tomak 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(4):559-564
The effects of asymmetry and the electric field on the
electronic subbands and the nonlinear intersubband optical
absorption of GaAs quantum wells represented by a P?schl-Teller
confining potential are studied. The potential itself can be made
asymmetric through a correct choice of its parameter set and this
adjustable asymmetry is important for optimizing the absorption. In
that way optimal cases can be created. We calculate the modified
wave functions and electronic subbands variationally. The linear and
the nonlinear optical intersubband absorption coefficients are
calculated. Numerical results for a typical GaAs quantum well are
presented. The nonlinear part of the absorption coefficient is
strongly modified by the asymmetry parameters while the electric
field affects it at smaller values of the parameters.
- 78.67.De Quantum wells 相似文献
10.
A. Biber A. Golick M. Tomak 《International Journal of Infrared and Millimeter Waves》2001,22(7):1019-1035
The paper presents results of numerical investigations of electromagnetic (optical) ray propagation inside a sphere, made of optically uniaxial crystal. The types of caustics formed by the ray trajectory inside the sphere are cleared up. It has been demonstrated the difference between types of caustics formed by the extraordinary ray trajectory inside the sphere made of optically positive and negative crystals. Results are discussed on the basis of one-to-one mapping of 2D billiard problem inside isotropic region bounded by ellipse onto anisotropic one. 相似文献