Theoretical Study of the Magneto-Thermoelectric Effect in Doped Semiconductor Superlattices under the Influence of an Electromagnetic Wave by Using a Quantum Kinetic Equation

2018 ◽  
Vol 783 ◽  
pp. 93-102 ◽  
Author(s):  
Dao Thu Hang ◽  
Nguyen Vu Nhan ◽  
Nguyen Quang Bau
Keyword(s):  
Kinetic Equation ◽  
Electromagnetic Waves ◽  
Quantum Kinetic Equation ◽  
Characteristic Parameters ◽  
Thermoelectric Effects ◽  
Semiconductor Superlattice ◽  
Bulk Semiconductors ◽  
Ettingshausen Effect ◽  
Electron Acoustic ◽  
The Impact

By using a quantum kinetic equation for electrons, we studied magneto - thermoelectric effects in the doped semiconductor superlattice (DSSL) under the influence of electromagnetic waves (EMW). In case of the electron - acoustic phonon interaction, we have also figured out analytical expressions of the Ettingshausen coefficient (EC) in DSSL. These expressions are quite different from those which were obtained in the case of bulk semiconductors. The results are numerically calculated for the GaAs:Be/ GaAs:Si DSSL; we found that the EC depends on the characteristic parameters of EMW, temperature and the characteristic parameters of DSSL. The results are consistent with recently experimental observations but the EC is different from that in the bulk semiconductors or bismuth. In addition, the impact of the EMW on the Ettingshausen effect was also discovered. These are latest results which have been studied in terms of Ettingshausen effect in DSSL.

scholarly journals Magneto – thermoelectric Effects in Compositional Superlattice in the Presence of Electromagnetic Wave

2019 ◽  
Vol 35 (3) ◽  
Author(s):  
Dao Thu Hang ◽  
Nguyen Thi Hoa ◽  
Nguyen Thi Thanh Nhan ◽  
Nguyen Quang Bau
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Kinetic Equation ◽  
Quantum Kinetic Equation ◽  
Thermoelectric Effects ◽  
Semiconductor Superlattice ◽  
Analytical Expressions ◽  
The Magnetic Field ◽  
Superlattice Period

Ettingshausen coefficient (EC) in the compositional semiconductor superlattice under the influence of electromagnetic wave (EMW) is surveyed by using the quantum kinetic equation for electrons.  The analytical expressions of the Ettingshausen coefficient are numerically calculated for the GaAs/AlGaAs compositional semiconductor superlattice. It have been showed that the appearance of EMW has changed the EC’s value and the EC decreases nonlinearly when the temperature increases. Studying the dependence of EC on the magnetic field, we discovered that the resonance peaks have appeared and the superlattice period strongly affects the Ettingshausen coefficient.  

scholarly journals Influence of Confined Acoustic Phonons on the Nonlinear Acousto-electric Effect in Doped Semiconductor Superlattices

2019 ◽  
Vol 35 (2) ◽  
Author(s):  
Nguyen Quyet Thang ◽  
Nguyen Dinh Nam ◽  
Nguyen Quang Bau
Keyword(s):  
Kinetic Equation ◽  
Acoustic Wave ◽  
Electric Current ◽  
Wave Frequency ◽  
Quantum Kinetic Equation ◽  
Characteristic Parameters ◽  
Phonon Interaction ◽  
Frequency Condition ◽  
Semiconductor Superlattice ◽  
Electron Phonon Interaction

Abstract: By using a quantum kinetic equation for electrons, we have studied the Acousto-electric effects in doped semiconductor superlattice (DSSL) under the influence of confined phonon. Considering the case of the electron - acoustic phonon interaction, we have found the expressions of the nonlinear quantum acousto-electric current. From these expression, the acousto-electric current (AEC) depends nonlinearly on temperature, acoustic wave frequency and the characteristic parameters of DSSL (For example: the doped concentration ). Moreover, the expression of the AEC under the influence of confined phonons fairly different from the case of unconfined phonons. The results are numerically calculated for the GaAs:Be/ GaAs:Si DSSL; therefore, it can be easily seen that the dependence of the acousto-electric current on the characteristic parameters of the acoustic wave, temperature, the characteristic parameters of DSSL and the quantum number m characterizing the phonons confinement. The results have showed that the appearance of phonons confinement make the AEC value changes remarkably. The AEC is almost stable in low acoustic wave frequency condition and changes as a parabolic curve when  move up. On the other hand, in case of low doped concentration number the AEC surges as a parabolic function in the dependence on , then it remains stability at just below zero in high  value. Keywords: Acousto-electric field, Quantum kinetic equation, Doped superlattices, Electron - phonon interaction.  

scholarly journals Magneto – thermoelectric effects in quantum well in the presence of electromagnetic wave

2017 ◽  
Vol 33 (2) ◽  
Author(s):  
Nguyen Quang Bau ◽  
Dao Thu Hang ◽  
Doan Minh Quang ◽  
Nguyen Thi Thanh Nhan
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Quantum Well ◽  
Quantum Kinetic Equation ◽  
Thermoelectric Effects ◽  
Parabolic Potential ◽  
Bulk Semiconductors ◽  
Sdh Oscillations ◽  
Analytic Expression ◽  
The Magnetic Field

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.  Keywords:  Ettingshausen, Quantum well, Electromagnetic wave, parabolic potential, GaAs/GaAsAl.

One-dimensional cylindrical quantum wire: The theoretical study of photo-stimulated Ettingshausen effect

2021 ◽  
Author(s):  
Hoang Van Ngoc ◽  
Nguyen Quang Bau ◽  
Doan Minh Quang ◽  
Tran Hai Hung
Keyword(s):  
Magnetic Field ◽  
Optical Phonon ◽  
Quantum Wire ◽  
Acoustic Phonon ◽  
Phonon Scattering ◽  
Resonance Effect ◽  
One Dimensional ◽  
Ettingshausen Effect ◽  
Electron Acoustic ◽  
The Impact

Based on the quantum kinetic equation (QKE) for electron, we have theoretically studied the theory of photo-stimulated Ettingshausen effect in a one-dimensional cylindrical quantum wire (CQW). The strong electromagnetic wave (EMW) [Formula: see text] plays a role as photo-stimulation source. We obtain the analytic expressions for the kinetic tensors [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and the Ettingshausen coefficient (EC) in the CQW with the dependence on the amplitude and the energy of EMW, the CQW radius, the magnetic field and the temperature for two cases: optical phonon and acoustic phonon. The results are numerically evaluated and graphed for GaAs/AlGaAs CQW model. It is shown that we observe the cyclotron resonance and magneto-phonon resonance effect while surveying EC in terms of magnetic field (with and without EMW) and EMW energy, considered the electron-optical phonon scattering. In case of electron-acoustic phonon scattering, the oscillation of EC is obtained with the transition between low Landau levels (LLs). We also clarify the impact of quantum size effect (QSE) on EC by surveying the influence of EC on the radius of CQW.

scholarly journals Calculation of the Ettingshausen coefficient in a Rectangular quantum wire with an infinite potential in the presence of an Electromagnetic wave (the electron - optical phonon interaction )

2017 ◽  
Vol 33 (4) ◽  
Author(s):  
Trần Hải Hưng
Keyword(s):  
Electromagnetic Wave ◽  
Optical Phonon ◽  
Quantum Wire ◽  
Characteristic Parameters ◽  
Phonon Interaction ◽  
Bulk Semiconductors ◽  
Ettingshausen Effect ◽  
The Difference ◽  
The Magnetic Field ◽  
Theoretical Results

The Ettingshausen coefficient (EC) in  a Rectangular quantum wire with an infinite potential (RQWIP)in the presence of an Electromagnetic wave (EMW) is calculated by using a quantum kinetic equation for electrons. Considering the case of the electron - optical phonon interaction, we have found the expressions of the kinetic tensors . From the kinetic tensors, we have also obtained the analytical expression of the EC in the RQWIP in the presence of EMW as function of the frequency and the intensity of the EMW, of the temperature of system, of the magnetic field  and of the characteristic parameters of RQWIP. The theoretical results for the EC are numerically evaluated, plotted and discussed for a specific RQWIP GaAs/GaAsAL. We also compared received EC with those for normal bulk semiconductors and quamtum wells to show the difference. The Ettingshausen effect in  a RQWIP in the presence of an EMW is newly developed.

scholarly journals Sterile Neutrinos as Dark Matter: Alternative Production Mechanisms in the Early Universe

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 264
Author(s):  
Daniel Boyanovsky
Keyword(s):  
Dark Matter ◽  
Distribution Function ◽  
Kinetic Equation ◽  
Standard Model ◽  
Early Universe ◽  
Quantum Kinetic Equation ◽  
Sterile Neutrinos ◽  
The Standard Model ◽  
Production Mechanisms ◽  
Freeze Out

We study various production mechanisms of sterile neutrinos in the early universe beyond and within the standard model. We obtain the quantum kinetic equations for production and the distribution function of sterile-like neutrinos at freeze-out, from which we obtain free streaming lengths, equations of state and coarse grained phase space densities. In a simple extension beyond the standard model, in which neutrinos are Yukawa coupled to a Higgs-like scalar, we derive and solve the quantum kinetic equation for sterile production and analyze the freeze-out conditions and clustering properties of this dark matter constituent. We argue that in the mass basis, standard model processes that produce active neutrinos also yield sterile-like neutrinos, leading to various possible production channels. Hence, the final distribution function of sterile-like neutrinos is a result of the various kinematically allowed production processes in the early universe. As an explicit example, we consider production of light sterile neutrinos from pion decay after the QCD phase transition, obtaining the quantum kinetic equation and the distribution function at freeze-out. A sterile-like neutrino with a mass in the keV range produced by this process is a suitable warm dark matter candidate with a free-streaming length of the order of few kpc consistent with cores in dwarf galaxies.

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