Scattering Processes with the Emission of Longitudinal Optical Phonons in the Landau Level System In GaAs/AlGaAs Quantum Well

2021 ◽  
Author(s):  
Ngo Vinh Doan The ◽  
Trung Le Canh
Keyword(s):  
Magnetic Field ◽  
Quantum Well ◽  
Quantum Wells ◽  
Golden Rule ◽  
Longitudinal Optical ◽  
Optical Phonons ◽  
Scattering Rate ◽  
Quantizing Magnetic Field ◽  
Scattering Time ◽  
The Magnetic Field

Abstract The scattering processes of longitudinal optical phonons in GaAs/AlGaAs quantum wells in a quantizing magnetic field are considered. The time of intrasubband scattering between Landau levels is calculated by using Fermi's golden rule. The dependence of the scattering rate on the magnitude of the magnetic field has been shown and the magnetic field can suppress scattering processes on longitudinal optical phonons. It is found that the scattering time depends linearly on the width of the quantum well.

Electron Subband Levels of n-Type δ-Doped Quantum Wells under In-Plane Magnetic Fields

1997 ◽  
Vol 11 (09) ◽  
pp. 1195-1207
Author(s):  
E. K. Takahashi ◽  
A. T. Lino ◽  
L. M. R. Scolfaro
Keyword(s):  
Magnetic Field ◽  
Electronic Structure ◽  
Magnetic Fields ◽  
Quantum Well ◽  
Quantum Wells ◽  
Conduction Band ◽  
Electron Energy ◽  
Self Consistent ◽  
Plane Direction ◽  
The Magnetic Field

Self-consistent calculations of the electronic structure of center n-δ-doped GaAs/Al x Ga 1-x As quantum wells under in-plane magnetic fields are presented. The field B is varied up to 20 Tesla for different quantum well widths L w and sheet donor concentrations N D . The magnetic field produces noticeable changes in the energy dispersions along an in-plane direction perpendicular to B. The effects of B are more pronounced for higher electronic subbands. It is found that the diamagnetic shifts increase with increasing L w and/or N D . Contrarily to what has been observed in modulation-doped quantum wells, in these δ-doped systems the electron energy dispersions keep the single conduction band minimum at the center of the Brillouin zone even for intense magnetic fields.

Electron–electron inter-subband scattering in GaAs quantum wells

1996 ◽  
Vol 74 (S1) ◽  
pp. 252-255
Author(s):  
Zhi Zhong Xu ◽  
D. Morris
Keyword(s):  
Quantum Well ◽  
Quantum Wells ◽  
Electron Scattering ◽  
Multiple Quantum Well ◽  
Golden Rule ◽  
Multiple Quantum ◽  
Hot Electron ◽  
Quantum Well Structures ◽  
Scattering Rate ◽  
Relaxation Channel

The role of electron–electron scattering in the dynamics of inter-subband relaxation in GaAs quantum wells is investigated theoretically. The scattering rate is calculated using the Fermi golden rule, as a function of the carrier densities. The dependence of the inter-subband relaxation time on the quantum-well width is also investigated. Calculations are performed for multiple quantum-well structures with well widths varying from 80 to 240 Å (1 Å = 10−10 m). The hot electron distribution and the subband occupation function are taken into account in these calculations. Results show that the electron–electron scattering rate increases linearly as a function of the carrier densities. A band-filling effect limits the efficiency of this mechanism under high carrier densities (> 1012 cm−2). For thick well (180 Å) structures, this relaxation channel is as efficient as the phonon relaxation channel.

COMPREHENSIVE STUDY OF SPIN-FLIP EXCITATIONS IN CdZnTe/CdZnMnTe QUANTUM WELLS

2007 ◽  
Vol 21 (08n09) ◽  
pp. 1610-1614
Author(s):  
DAISUKE FUKUOKA ◽  
KOUSHIRO ARAHARA ◽  
TAKAAKI KOYAMA ◽  
NAOKI TANAKA ◽  
KENICHI OTO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Well ◽  
Quantum Wells ◽  
Electron Spin ◽  
Energy Difference ◽  
Magnetic Field Direction ◽  
Kerr Rotation ◽  
Spin Configuration ◽  
Spin Flip ◽  
The Magnetic Field

Spin-flip excitations in non-doped Cd 0.93 Zn 0.07 Te/Cd 0.48 Zn 0.04 Mn 0.48 Te quantum wells have been comprehensively studied by spin-flip Raman scattering (SFRS) spectroscopy and time-resolved Kerr rotation (TRKR) spectroscopy. In 4 nm quantum well, two spin-flip Raman peaks were observed in addition to the multiple Mn 2+ spin-flip scatterings. The spin-flip energies are isotropic against the magnetic field direction and well described by modified Brillouin functions. Based on the circumstantial analysis, they are assigned to the spin-flip of residual electrons and the electron spin-flip in the localized exciton, respectively, even though the large energy difference between the two electron spin-flip processes is a puzzle. While, in 9 nm quantum well a strange spin-flip excitation was observed together with a very weak Mn 2+ spin-flip scattering. The spin-flip energy changed strangely up to the magnetic field 4T, and then linearly increased with field (| g *|=1.15). A high-resolution TRKR spectroscopy revealed an unusual temperature dependence, which resembled "softening mode" of spin resonance observed in p-doped ferromagnetic CdMnTe quantum wells. However, these behaviors are well understood by an "inverted spin configuration", which results from a negative g*-factor and a very weak s-d interaction between the electrons and the manganese ions in the barrier.

Thermoelectric Power in Quantum Confined Bismuth Under Classically Large Magnetic Field

1990 ◽  
Vol 216 ◽  
Author(s):  
Kamakhya P. Ghatak ◽  
S. N. Biswas
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Quantum Well ◽  
Film Thickness ◽  
Quantum Wells ◽  
Thermoelectric Power ◽  
Large Magnetic Field ◽  
Quantum Well Wires ◽  
Electron Dispersion ◽  
Theoretical Results

ABSTRACTIn this paper we studied the thermoelectric power under classically large magnetic field (TPM) in quantum wells (QWs), quantum well wires (QWWS) and quantum dots (QDs) of Bi by formulating the respective electron dispersion laws. The TPM increases with increasing film thickness in an oscillatory manner in all the cases. The TPM in QD is greatest and the least for quantum wells respectively. The theoretical results are in agreement with the experimental observations as reported elsewhere.

Theoretical Investigation of the Shubnikov-de Haas Magnetoresistance Oscillations in a Quantum well under the Influence of Confined Acoustic Phonons

2018 ◽  
Vol 783 ◽  
pp. 1-11
Author(s):  
Le Thai Hung ◽  
Pham Ngoc Thang ◽  
Nguyen Quang Bau
Keyword(s):  
Magnetic Field ◽  
Quantum Well ◽  
Phonon Confinement ◽  
Acoustic Phonons ◽  
Magnetic Impedance ◽  
Magnetoresistance Oscillations ◽  
The Magnetic Field ◽  
Amplitude Decrease ◽  
Theoretical Results ◽  
Phonon Confinement Effect

The Shubnikov – de Haas magnetoresistance oscillations in the Quantum well (QW) under the influence of confined acoustic phonons, The theoretical results show that the conductivity tensor, the complex magnetic impedance of the magnetic field, the frequency, the amplitude of the laser radiation, the QW width, the temperature of the system and especially the quantum index m characterizes the confinement of the phonon. The amplitude of the oscillations of the Shubnikov-de Haas impedance decreases with the increase of the influence of the confined acoustic phonons. The results for bulk phonons in a QW could be achieved, when m goes to zero. We has been compared with other studies when perform the numerical calculations are also achieved for the GaAs/AlGaAs in the QW. Results show that The Shubnikov-de Haas magnetoresistance oscillations amplitude decrease when phonon confinement effect increasing and when width L of the QW increases to a certain value, The Shubnikov – de Haas magnetoresistance oscillations amplitude completely disappears can not be observed.

scholarly journals Квантовые осцилляции релаксации фотопроводимости в p-i-n-гетеродиодах GaAs/InAs/AlAs

2018 ◽  
Vol 52 (6) ◽  
pp. 591
Author(s):  
Ю.Н. Ханин ◽  
Е.Е. Вдовин
Keyword(s):  
Magnetic Field ◽  
Quantum Well ◽  
Oscillation Amplitude ◽  
Light Flux ◽  
Quantum Oscillations ◽  
Ballistic Motion ◽  
The Common ◽  
Relaxation Curves ◽  
Relaxation Characteristics ◽  
The Magnetic Field

AbstractThe photoconductivity and its relaxation characteristics in tunneling p – i – n GaAs/AlAs heterostructures under pulsed illumination is studied. Quantum oscillations in the photoconductivity are detected depending on the bias voltage with the period independent of the light wavelength, as well as an oscillating component of the relaxation curves caused by modulation of the recombination rate at the edge of a triangular quantum well in the undoped i layer, as in the case of photoconductivity oscillations. The common nature of oscillations of the steady-state photoconductivity and relaxation curves under pulsed illumination is directly confirmed by the lack of an oscillating component in both types of dependences of some studied p–i–n heterostructures. Simultaneous suppression of the observed oscillations of dependences of both types as the temperature increases to 80 K also confirms the proposed mechanism of their formation. The dependences of these oscillations on the magnetic field and light flux power are studied. Oscillation-amplitude suppression in a magnetic field of ~2 T perpendicular to the current is caused by the effect of the Lorentz force on the ballistic motion of carriers in the triangular-quantum-well region.

scholarly journals Grating Metamaterials Based on CdTe/CdMgTe Quantum Wells as Terahertz Detectors for High Magnetic Field Applications

2020 ◽  
Vol 10 (8) ◽  
pp. 2807
Author(s):  
Dmitriy Yavorskiy ◽  
Maria Szoła ◽  
Krzysztof Karpierz ◽  
Rafał Bożek ◽  
Rafał Rudniewski ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electron Beam ◽  
Quantum Well ◽  
Quantum Wells ◽  
Atomic Force Microscope ◽  
High Magnetic Field ◽  
White Light ◽  
Electron Beam Lithography ◽  
Terahertz Detectors ◽  
Atomic Force

The cyclotron and magnetoplasmon resonances were studied at 2 K in grating metamaterials fabricated on wafers with one or two modulation doped CdTe/CdMgTe quantum wells. The gratings (with the period varied between 2 μ m and 8 μ m) were prepared with an electron beam lithography either by etching or by evaporation of Au. The gratings were studied with an atomic force microscope which revealed a correlation between the depth and width of etched grooves at a constant time of etching. The sharpest resonances observed are due to excitation of magnetoplasmon in the case of Au gratings on a wafer with one quantum well. Etched samples with two quantum wells showed the strongest tuneability of magnetoplasmon resonances with the period of the grating and illumination with white light. We showed that the samples studied can be used as resonant or quasi-resonant terahertz detectors tuneable with magnetic field and white light.

Effect of the magnetic field on optical properties of GaN/AlN multiple quantum wells

2013 ◽  
Vol 134 ◽  
pp. 88-95 ◽  
Author(s):  
M. Solaimani ◽  
Morteza Izadifard ◽  
H. Arabshahi ◽  
Sarkardei Mohammad Reza
Keyword(s):  
Magnetic Field ◽  
Optical Properties ◽  
Quantum Wells ◽  
Multiple Quantum Wells ◽  
Multiple Quantum ◽  
The Magnetic Field

Free-carrier screening of the interaction between excitons and longitudinal-optical phonons inInxGa1−xAs-InP quantum wells

1987 ◽  
Vol 35 (11) ◽  
pp. 5925-5928 ◽  
Author(s):  
M. S. Skolnick ◽  
K. J. Nash ◽  
P. R. Tapster ◽  
D. J. Mowbray ◽  
S. J. Bass ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Longitudinal Optical ◽  
Carrier Screening ◽  
Free Carrier ◽  
Optical Phonons
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