TRANSITION FREQUENCY OF WEAK-COUPLING IMPURITY BOUND MAGNETOPOLARON IN AN ANISOTROPIC QUANTUM DOT

2012 ◽  
Vol 26 (01) ◽  
pp. 1150003 ◽  
Author(s):  
CHENG-SHUN WANG ◽  
JING-LIN XIAO
Keyword(s):  
Magnetic Field ◽  
Excited State ◽  
Quantum Dot ◽  
Weak Coupling ◽  
State Energy ◽  
Cyclotron Frequency ◽  
Excited State Energy ◽  
First Excited State ◽  
Anisotropic Quantum Dot ◽  
The Magnetic Field

We study the first excited-state energy, the excitation energy and the transition frequency between the first excited- and the ground-state of weak-coupling magnetopolaron in an anisotropic quantum dot. The effects of the Coulomb bound potential, the cyclotron frequency of the magnetic field, the electron–phonon interaction and the transverse and the longitudinal effective confinement lengths are taken into account by using the linear combination operator method. It is found that studied quantities will increase with increasing Coulomb bound potential and the cyclotron frequency of the magnetic field. They are decreasing functions of the effective confinement lengths, which can be attributed to the interesting quantum size confining effect. The first excited-state energy is a decreasing function of the electron–phonon coupling strength.

INFLUENCE OF LATTICE VIBRATION ON THE GROUND STATE OF MAGNETOPOLARON IN A PARABOLIC QUANTUM DOT

2010 ◽  
Vol 24 (27) ◽  
pp. 2705-2712 ◽  
Author(s):  
EERDUNCHAOLU ◽  
WEI XIN ◽  
YUWEI ZHAO
Keyword(s):  
Magnetic Field ◽  
Strong Coupling ◽  
Ground State Energy ◽  
Vibration Frequency ◽  
Ground State ◽  
Weak Coupling ◽  
State Energy ◽  
Cyclotron Frequency ◽  
Lattice Vibration ◽  
The Magnetic Field

Influence of the lattice vibration on the properties of the magnetopolaron in the parabolic quantum dots (QDs) is studied by using the Huybrechts' linear combination operator and Lee–Low–Pines (LLP) transformation methods. The expressions for the vibration frequency and the ground-state energy of the magnetopolaron as functions of the confinement strength of the QDs, the magnetic field and temperature are derived under the strong and weak coupling, respectively. The results of the numerical calculations show that the changes of the vibration frequency and ground-state energy of the magnetopolaron with the confinement strength of the QDs, the magnetic field and temperature are different under different couplings. The vibration frequency and the ground-state energy of the weak-coupling magnetopolaron and the vibration frequency of the strong-coupling magnetopolaron will increase with increase of the confinement strength of the QDs and cyclotron frequency, the vibration frequency and ground-state energy of the strong-coupling magnetopolaron. However, the ground-state energy of the weak-coupling magnetopolaron will decrease with increase of the temperature. The dependence of the ground-state energy of the strong-coupling magnetopolaron on the confinement strength of the QDs and cyclotron frequency is strongly influenced by the temperature. The remarkable influence of the temperature on the ground-state energy of the magnetopolaron arises when the temperature is relatively higher.

Evaluation of AlGaAs/GaAs Heterointerface by Shubnikov-de Haas Oscillation Measurements

1986 ◽  
Vol 77 ◽  
Author(s):  
Kazumi Kasai ◽  
H. Tanaka ◽  
H. Itoh ◽  
T. Oh-Hori ◽  
M. Takikawa ◽  
...  
Keyword(s):  
Excited State ◽  
State Energy ◽  
Energy Levels ◽  
Interface Model ◽  
Dimensional Electron ◽  
Excited State Energy ◽  
Haas Oscillation ◽  
First Excited State ◽  
A New Technique

ABSTRACTThe measurement of Shubnikov-de Haas(SdH) oscillation is proposed as a new technique for evaluating the quality of a heterointerface. The first excited state of 2-dimensional electron energy levels is determined for several samples using the measurements of SdH oscillation. Lower values of the first excited state energy are found for the samples with a low mobility. The low value can be approximately explained in terms of graded interface model.

First-excited-state energy of hydrogenic impurity bound polaron in an anisotropic quantum dot in an electric field

2019 ◽  
Vol 33 (32) ◽  
pp. 1950386
Author(s):  
Shi-Hua Chen
Keyword(s):  
Excited State ◽  
Binding Energy ◽  
Quantum Dot ◽  
Electric Field ◽  
Binding Energies ◽  
Hydrogenic Impurity ◽  
Bound Polaron ◽  
First Excited State ◽  
Trial Wavefunction ◽  
Anisotropic Quantum Dot

The first-excited-state (ES) binding energy of hydrogenic impurity bound polaron in an anisotropic quantum dot (QD) is obtained by constructing a variational wavefunction under the action of a uniform external electric field. As for a comparison, the ground-state (GS) binding energy of the system is also included. We apply numerical calculations to KBr QD with stronger electron–phonon (E–P) interaction in which the new variational wavefunction is adopted. We analyzed specifically the effects of electric field and the effects of both the position of the impurity and confinement lengths in the xy-plane and the [Formula: see text] direction on the ground and the first-ES binding energies (BEs). The results show that the selected trial wavefunction in the ES is appropriate and effective for the current research system.

Shannon entropy and decoherence of bound magnetopolaron in a modified cylindrical quantum dot

2015 ◽  
Vol 29 (35n36) ◽  
pp. 1550241 ◽  
Author(s):  
A. J. Fotue ◽  
S. C. Kenfack ◽  
M. Tiotsop ◽  
N. Issofa ◽  
A. V. Wirngo ◽  
...  
Keyword(s):  
Excited State ◽  
Quantum Dot ◽  
Density Matrix ◽  
Shannon Entropy ◽  
Ground State ◽  
Superposition State ◽  
First Excited State ◽  
Coupling Strengths ◽  
The Magnetic Field ◽  
Bound Magnetopolaron

In this paper, we calculate the time evolution of the quantum mechanical state of a bound magnetopolaron in a modified cylindrical quantum dot. In the condition of strong coupling, we investigate the eigen energies and the eigenfunctions of the ground state and the first excited state, respectively. This system may be employed as a two-level quantum system qubit and therefore be helpful for storage of information. The Shannon entropy is used to investigate the decoherence of the qubit when the latter is in the superposition state of the ground and the first excited states. We also study the influence of the electric field, the magnetic field and the Coulomb potential on the decoherence time, eigen energies of the ground state, and the first excited state. It is shown that, the phonon spontaneous emission causes the decoherence of the qubit. We plot the decay of the density matrix of the qubit and the coherent term of the density matrix element [Formula: see text] (or [Formula: see text]) in a function of time for different coupling strengths, confinement lengths and dispersion coefficient.

Electron and Hole Levels in Rectangular Quantum Wires

2013 ◽  
Vol 380-384 ◽  
pp. 4833-4836
Author(s):  
Guang Xin Wang ◽  
Xiu Zhi Duan
Keyword(s):  
Magnetic Field ◽  
Ground State ◽  
State Energy ◽  
Quantum Wires ◽  
Excited State Energy ◽  
Mass Approximation ◽  
First Excited State ◽  
Diagonalization Method ◽  
The Wire ◽  
Rectangular Quantum Wires

Within the effective mass approximation and the diagonalization method, the problem of electron and hole levels in rectangular quantum wires (QWRs) is investigated in detail. The mismatch of material mass between the wire and the barrier and anisotropy of the hole mass is considered in our calculation. We study the ground-state energy and the first excited-state energy for the case of a magnetic field applied along the wire. The quantum behaviors are similar to that of other QWRs which were studied before.

GROUND AND EXCITED STATE PHOTOLUMINESCENCE MAPPING ON InAs/InGaAs QUANTUM DOT STRUCTURES

2007 ◽  
Vol 06 (05) ◽  
pp. 383-387
Author(s):  
T. V. TORCHYNSKA ◽  
E. VELÁZQUEZ LOZADA ◽  
M. DYBIEC ◽  
S. OSTAPENKO ◽  
P. G. ELISEEV ◽  
...  
Keyword(s):  
Excited State ◽  
Quantum Dot ◽  
Excited States ◽  
Long Range ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Excited State Energy ◽  
Photoluminescence Study ◽  
Range Variation

This paper presents the photoluminescence study at 12 K and scanning photoluminescence spectroscopy investigation of the ground and excited states at 80 and 300 K on InAs QDs inserted in In 0.15 Ga 0.85 As / GaAs QW structures and created at different QD growth temperatures. It is shown that investigated structures are characterized by the long range variation of an average QD size in QD ensemble across the wafer. This long range QD size inhomogeneity was used for investigation of the multi-excited state energy trend versus ground state energy (or QD sizes).

GROUND STATE ENERGIES OF HYDROGEN-LIKE IMPURITY IN A LENS-SHAPED QD

2004 ◽  
Vol 18 (17n19) ◽  
pp. 2529-2533 ◽  
Author(s):  
XIANGHUA ZENG ◽  
JIAFENG CHANG ◽  
PENGXIA ZHOU
Keyword(s):  
Magnetic Field ◽  
Quantum Dot ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Lateral Deviation ◽  
Mass Approximation ◽  
The Magnetic Field ◽  
Ground State Energies ◽  
Electronic Ground

In this paper,the ground state energies of hydrogen-like impurity in a lens-shaped quantum dot ( GaAs / In 1-x Ga x As ) under vertical magnetic field have been discussed by using effective mass approximation and variational method. It gives that for a lens-shaped quantum dot, due to the asymmetry of the vertical and lateral bound potentials, the electronic ground state energies are related not only with the deviation distance but also with the deviation direction; for the spherical quantum dot, the ground state energy is only related with the distance of the impurity deviation, neither with vertical nor lateral deviation. And with the increasing of the magnetic field, the ground state energy is increasing.

Research on Information Applied Technology in the Study of Two-Layer Quantum Dots System

2013 ◽  
Vol 473 ◽  
pp. 133-136
Author(s):  
An Mei Wang
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Ground State ◽  
Weak Coupling ◽  
State Energy ◽  
Electron System ◽  
Exact Diagonalization ◽  
Hamiltonian Matrix ◽  
Applied Technology ◽  
The Magnetic Field

We study a two-electron system in a double-layer quantum dot under a magnetic field by means of the exact diagonalization of the Hamiltonian matrix. We find that discontinuous ground-state energy transitions are induced by an external magnetic field in the case of strong coupling. However, in the case of weak coupling, the angular momentum of the true ground state does not change in accordance with the change of the magnetic field B and remains = 0.

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