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Photo-stimulated quantum thermo-magnetoelectric effects in doped two-dimensional semiconductor superlattices, including the photo-stimulated quantum Ettingshausen effect and the photostimulated quantum Peltier effect, have been theoretically studied by using the quantum kinetic equation method. In this work, we assume that the electron-confined acoustic phonon scattering is essential. Moreover, the presence of the laser radiation (LR) is also taken into account to determine the influence of confined phonons on the aforementioned effects. We have defined the analytical expressions for the kinetic tensors and the Ettingshausen and the Peltier coefficients, presented the numerically calculated the theoretical results for the GaAs:Si/GaAs:Be doped semiconductor superlattice and compared them with these for the case of an unconfined acoustic phonon. The results obtained indicated that the formulas for the kinetic tensors, the Ettingshausen coefficient (EC) and the Peltier coefficient (PC) contain the quantum number m specifying the confinement of a phonon and approach the results for an unconfined phonon as m goes to zero. We found that the kinetic tensors, the EC and the PC oscillate with changing magnetic field and that the confinement of a phonon causes a shift of the peaks in these oscillations to lower energy. The dependences of both EC and PC on the temperature were found to be nonlinear. Moreover, all the coefficients level off when the temperature was less than 4.5 K or greater than 5.5 K. The EC also depended on the doping concentration in a nonlinear way and reaches a positive constant value when the semiconductor superlattice was doped with a high concentration. Most of the numerical results showed that the magnitude of the tensors, the EC as well as the PC, within a confined acoustic phonon varie significantly in comparison with the unconfined phonon case. This means that the confinement of the phonon affects the thermo-magnetoelectric effect quantitatively and qualitatively. These results contribute to completing the theory of the thermo-magnetoelectric effects in the low-dimensional semiconductor systems.

The influences of confined phonons on the nonlinear absorption coefficient (NAC) by a strong electromagnetic wave for the case of electron-optical phonon scattering in doped superlattices (DSLs) are theoretically studied by using the quantum transport equation for electrons. The dependence of NAC on the energy (Ω), the amplitude E 0 of external strong electromagnetic wave, the temperature (T) of the system, is obtained. Two cases for the absorption: Close to the absorption threshold |k Ω − ω 0 | ε and far away from the absorption threshold |k Ω − ω 0 | ε (k = 0, ±1, ±2,. .. , ω 0 andε are the frequency of optical phonon and the average energy of electrons, respectively) are considered. The formula of the NAC contains a quantum number m characterizing confined phonons. The analytic expressions are numerically evaluated, plotted and discussed for a specific of the n-GaAs/p-GaAs DSLs. The computations show that the spectrums of the NAC in case of confined phonon are much different from they are in case of unconfined phonon and strongly depend on a quantum number m characterizing confinement phonon.

Abstract:We have studied magneto-thermoelectric effects in quantum well in the presence of electromagnetic wave. The analytic expression for Ettingshausen coefficient (EC) in the Quantum Well with parabolic potential (QWPP) in the presence of Electromagnetic wave (EMW) is calculated by using the quantum kinetic equation for electrons. The dependence of EC on the frequency, the amplitude of EMW, the Quantum Well parameters and the temperature are obtained. The results are numerically calculated, plotted, and discussed for GaAs/GaAsAl Quantum Well to clearly show the dependence of EC on above parameters and the results in this case are compared with the case in the bulk semiconductors. We realize that as the temperature increases, the EC decreases. The results show appearance of the Shubnikov-de Haas (SdH) oscillations when we survey the dependence of EC on the magnetic field.

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