The electronic states and magnetization of coupled AlGaAs/GaAs quantum dots in magnetic fields

2018 ◽  
Vol 32 (02) ◽  
pp. 1850011 ◽  
Author(s):  
Eshtiaq Hijaz ◽  
Mohammad K. Elsaid
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Ground State ◽  
Theoretical Study ◽  
Electronic States ◽  
Exact Diagonalization ◽  
Interacting Electrons ◽  
Diagonalization Method ◽  
Exact Diagonalization Method ◽  
Good Agreement

We present a theoretical study of electronic states and magnetization of two interacting electrons confined in coupled quantum dots (CQDs) presented in a magnetic field. We obtain the eigenenergies of the CQD by solving the relative two-dimensional (2D) Hamiltonian using the combined variational–exact diagonalization method. The dependence of magnetization on temperature, magnetic field strength, confining frequency and barrier height has been investigated. We have shown the singlet–triplet transitions in the ground state of the CQD spectra and the corresponding jumps in the magnetization curves. The comparisons show that our results are in very good agreement with the reported works.

scholarly journals The Effects of Pressure and Temperature on the Magnetic Susceptibility of Semiconductor Quantum Dot in A Magnetic Field

2017 ◽  
Vol 9 (1) ◽  
pp. 77 ◽  
Author(s):  
Faten BZOUR ◽  
Mohammad K. ELSAID ◽  
Ayham SHAER
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Quantum Dot ◽  
Theoretical Study ◽  
External Pressure ◽  
Diagonalization Method ◽  
Electron Quantum ◽  
Exact Diagonalization Method ◽  
Good Agreement ◽  
Parabolic Quantum Dot

In this work, we present a theoretical study of the magnetic susceptibility (x of two-electron GaAs parabolic quantum dot (QD) under the combined effects of external pressure, temperature and magnetic field. We used the exact diagonalization method to obtain the eigenenergies by solving the two electron quantum dot Hamiltonian taking into account the dependence of the effective mass and dielectric constant on the hydrostatic pressure and temperature. The pressure and temperature show significant effects on the calculated QD spectra. Next, we investigate the behavior of the magnetization of a quantum dot as a function of external pressure, temperature, confining frequency and magnetic field. The singlet-triplet transitions in the ground state of the quantum dot spectra and the corresponding jumps in the magnetic susceptibility spectra have been shown. The comparison shows that our results are in very good agreement with the reported works.

Four Interacting Electrons in a Vertically Coupled Quantum Dots

2012 ◽  
Vol 468-471 ◽  
pp. 1810-1813
Author(s):  
An Mei Wang ◽  
Peng Wang ◽  
Li Bo Fan
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Ground State ◽  
Weak Coupling ◽  
State Transition ◽  
Exact Diagonalization ◽  
Energy Spectra ◽  
Hamiltonian Matrix ◽  
Ground State Transition ◽  
Interacting Electrons

We studied the ground-state-transition of a vertically coupled four-layer single electron QDs system under a magnetic field by the exact diagonalization of the Hamiltonian matrix. For S=0, the energy spectra of the Dots are calculated as a function of applied magnetic field. We found discontinuous ground-state-transition induced by an external magnetic field in the case of strong coupling. However, in the case of weak coupling, such a transition does not occur.

The magnetization and magnetic susceptibility of GaAs Gaussian quantum dot with donor impurity in a magnetic field

2019 ◽  
Vol 33 (34) ◽  
pp. 1950422 ◽  
Author(s):  
Mohammad Elsaid ◽  
Mohamoud Ali ◽  
Ayham Shaer
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Quantum Dot ◽  
Theoretical Study ◽  
Donor Impurity ◽  
Confinement Potential ◽  
Potential Depth ◽  
Diagonalization Method ◽  
Electron Quantum ◽  
Exact Diagonalization Method

We present a theoretical study to investigate the effect of donor impurity on the magnetization (M) and the magnetic susceptibility [Formula: see text] of single electron quantum dot (QD) with Gaussian confinement in the presence of a magnetic field. We solve the Hamiltonian of this system, including the spin, by using the exact diagonalization method. The ground state binding energy (BE) of an electron has been shown as a function of QD radius and confinement potential depth. The behaviors of the magnetization and the magnetic susceptibility of a QD have been studied as a function of temperature, confinement potential depth, quantum radius and magnetic field. We have shown the effect of donor impurity on the magnetization and magnetic susceptibility curves of Gaussian quantum dot (GQD).

FOUR-ELECTRON SYSTEMS CONFINED IN MULTILAYER QUANTUM DOTS

2007 ◽  
Vol 21 (21) ◽  
pp. 1399-1413 ◽  
Author(s):  
WENFANG XIE
Keyword(s):  
Quantum Dots ◽  
Angular Momentum ◽  
Ground State ◽  
Electronic Structures ◽  
Electron Interaction ◽  
Magic Numbers ◽  
Electron Systems ◽  
Diagonalization Method ◽  
Exact Diagonalization Method ◽  
Ground State Electron

In this paper, we studied four-electron systems confined in one-, two-, and four-layer quantum dots, by the exact diagonalization method. A vertical magnetic field to the confinement plane is considered. The ground-state electronic structures and the spin and angular momentum transitions for different magnetic fields are investigated. Series of magic numbers of angular momentum which minimize the ground-state electron–electron interaction energy have been discovered. These are connected to the exchange and rotational symmetries of the systems.

The Study of Three-Layer Quantum Dots System

2012 ◽  
Vol 224 ◽  
pp. 371-374
Author(s):  
An Mei Wang
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Ground State ◽  
State Transition ◽  
Exact Diagonalization ◽  
Single Electron ◽  
Hamiltonian Matrix ◽  
Ground State Transition

we studied the ground-state-transition of a vertically coupled three-layer single electron QDs system under a magnetic field by the exact diagonalization of the Hamiltonian matrix.

Ground state properties of an anisotropic bilinear-biquadratic model

2014 ◽  
Vol 28 (20) ◽  
pp. 1450163
Author(s):  
Jinlong Wang
Keyword(s):  
Critical Point ◽  
Ground State ◽  
Exact Diagonalization ◽  
Spin Model ◽  
Total Spin ◽  
Anisotropic Parameter ◽  
One Dimensional ◽  
Anisotropic Properties ◽  
Diagonalization Method ◽  
Exact Diagonalization Method

In this paper, we consider anisotropic properties of a one-dimensional bilinear-biquadratic spin model with S = 1. The Hamiltonian with anisotropic parameter is studied numerically by using Lanczos exact diagonalization method at a critical point. It is found that the momentum corresponding to the ground state is affected by anisotropic parameter regularly, especially when total spin z-component is not zero.

Pressure and Temperature Effects on the Magnetic Properties of Donor Impurities in a GaAs/AlGaAs Quantum Heterostructure Subjected to a Magnetic Field

2021 ◽  
Vol 14 (3) ◽  
pp. 231-238
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Uniform Magnetic Field ◽  
Growth Direction ◽  
Exact Diagonalization ◽  
Donor Impurity ◽  
Diagonalization Method ◽  
Exact Diagonalization Method ◽  
Pressure And Temperature Effects ◽  
The Magnetic Field

Abstract: The exact diagonalization method has been used to solve the effective-mass Hamiltonian of a single electron confined parabolically in the GaAs/AlGaAs quantum heterostructure, in the presence of a donor impurity and under the effect of an applied uniform magnetic field. The donor impurity is located at distance (d) along the growth direction which is perpendicular to the motion of the electron in a two-dimensional heterostructure layer. We have investigated the dependence of the magnetization (M) and magnetic susceptibility (χ) of a GaAs/AlGaAs quantum heterostructure nanomaterial on the magnetic field strength (ω_c), confining frequency (ω_o), donor impurity position (d), pressure (P) and temperature (T). Keywords: Exact diagonalization, Donor impurity, Magnetic field, Magnetization, Magnetic susceptibility, Pressure and temperature.

scholarly journals Спиновая динамика отрицательно заряженных экситонов в квантовых точках InP/(In,Ga)P в магнитном поле

2020 ◽  
Vol 62 (11) ◽  
pp. 1816
Author(s):  
С.В. Некрасов ◽  
Ю.Г. Кусраев ◽  
И.А. Акимов ◽  
L. Langer ◽  
M. Kotur ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Quantum Dots ◽  
Circular Polarization ◽  
Ground State ◽  
Heavy Hole ◽  
Spin Dynamics ◽  
Nuclear Spins ◽  
Time Resolved ◽  
Exciton Ground State ◽  
Charged Exciton

The dynamics of the photoluminescence negative circular polarization of the InP/(In,Ga)P quantum dots ensemble was studied. We find that in the time-resolved dependences of the polarization there are no oscillations in Voigt magnetic field. Also, with increasing field the polarization declines to zero. Such behavior is attributed to the peculiarities of the negatively charged exciton spin dynamics, particularly, to the fact that in the negatively charged exciton ground state the spin dynamics is governed by the heavy hole. We show that magnetic field depolarization of the photoluminescence occurs once the field of dynamically polarized nuclear spins acting on electron spins is surpassed.

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