Effects of Strong Coupling Magnetopolaron in Quantum Dot

1998 ◽  
Vol 12 (17) ◽  
pp. 693-701 ◽  
Author(s):  
Haiyang Zhou ◽  
Shiwei Gu ◽  
Yaoming Shi
Keyword(s):  
Excited State ◽  
Quantum Dot ◽  
Variational Method ◽  
Strong Coupling ◽  
Ground State ◽  
Cyclotron Resonance ◽  
State Energy ◽  
Two Dimensional ◽  
Excited State Energy ◽  
Limiting Case

With the use of variational method of Pekar type, we have calculated both the ground state energy and the excited state energy of strong coupling magnetopolaron in disk-shape quantum dot. The dependence of cyclotron resonance frequency of magnetopolaron on the magnetic eld and the confinement strength of quantum dot and quantum well is depicted. The limiting case of bulk type and strict two-dimensional type is discussed.

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).

Study of strong-coupling impurity bound polaron in a quantum pseudodot

2015 ◽  
Vol 29 (09) ◽  
pp. 1550058 ◽  
Author(s):  
R. Khordad
Keyword(s):  
Excited State ◽  
Quantum Dot ◽  
Strong Coupling ◽  
Coupling Strength ◽  
State Energy ◽  
Transition Frequency ◽  
Excited State Energy ◽  
Quantum Pseudodot ◽  
Bound Polaron ◽  
Potential Height

In the present work, we have studied the first internal excited state energy and transition frequency of strong-coupling impurity bound polaron in a quantum pseudodot using the well-known Lee–Low–Pines (LLP) unitary transformation method. We show the effect of Coulomb bound potential, electron–phonon (e–p) coupling strength, the quantum dot radius and potential height on first internal excited state energy and the transition frequency of the impurity bound polaron. According to the results, it is found that the first internal excited state energy is decreased with increasing quantum dot radius. Also, this energy is increased with enhancing potential height. The transition frequency is increased with increasing the e–p coupling strength. Also, the first internal excited state energy is increased with decreasing the e–p coupling strength. The transition frequency is enhanced with increasing the Coulomb bound potential.

Nonlinear absorption coefficient and refractive index changes of two-dimensional two-electron quantum dot in rigid confinement

2019 ◽  
Vol 33 (09) ◽  
pp. 1950078
Author(s):  
Menberu Mengesha Woldemariam
Keyword(s):  
Refractive Index ◽  
Excited State ◽  
Quantum Dot ◽  
Absorption Coefficient ◽  
Ground State ◽  
State Energy ◽  
Two Dimensional ◽  
First Excited State ◽  
Trial Wavefunction ◽  
Index Changes

The Hamiltonian and wavefunctions describing two-dimensional (2D) two-electron ZnO quantum dot in rigid confinement are developed. Then the Schrödinger equation is solved analytically and numerically for determining the ground and excited state energies. The ground state energy of 2D two-electron ZnO quantum dot (QD) in rigid confinement is studied using perturbation and variational methods. The obtained result show that our trial wavefunction is good enough to describe the 2D two-electron QD in rigid confinement. The wavefunction describing the ground state is the combination of symmetric spatial wavefunction and antisymmetric spin wavefunction which is a para-state. The ground state energy eigenvalue obtained by variational technique is a little above that of a perturbation technique. Based on this; the trial wavefunction for the excited state is developed. The excited state energy of 2D two-electron ZnO QD in rigid confinement is studied computationally using variational method. The wavefunction describing the excited state is the combination of symmetric spatial wavefunction with antisymmetric spin wavefunction (para-state) or vice versa (ortho-state). The para and ortho-state energies of the first excited state are calculated and their difference is twice of the exchange energy. Based on the obtained energy eigenvalues of the ground and the first excited state at the value of the coupling constant [Formula: see text] [Formula: see text] 1, the third-order nonlinear absorption coefficient and refractive index changes are investigated. The optical transition is only considered between the two lowest para states.

GROUND STATE LIFETIME OF STRONG-COUPLING MAGNETOPOLARON IN AN ASYMMETRIC QUANTUM DOT

2009 ◽  
Vol 23 (12) ◽  
pp. 1547-1555 ◽  
Author(s):  
ZHIXIN LI ◽  
JINGLIN XIAO
Keyword(s):  
Quantum Dot ◽  
Strong Coupling ◽  
Ground State Energy ◽  
Vibration Frequency ◽  
Ground State ◽  
Coupling Strength ◽  
State Energy ◽  
External Temperature ◽  
Asymmetric Quantum Dot ◽  
Asymmetric Quantum

The ground state lifetime of a magnetopolaron was investigated with electron–LO-phonon strong coupling in an asymmetric quantum dot using the linear combination operator and unitary transformation methods. Quantum transition, which cause changes of the magnetopolaron lifetime, occurs in the quantum system due to electron–phonon interaction and the influence of external temperature, that is, the magnetopolaron leaps from the ground state to the first excited state after absorbing a LO-phonon. The expressions of the ground state lifetime of the magnetopolaron as a function of the ground state energy, the transverse and longitudinal confinement lengths of quantum dot, the electron–phonon coupling strength, the cyclotron vibration frequency and the external temperature were obtained. Numerical calculations have been performed and the results show that the ground state lifetime of the magnetopolaron increases with increasing the ground state energy and the cyclotron vibration frequency, and decreases with increasing the transverse and longitudinal confinement lengths of the quantum dot, the coupling strength and the external temperature.

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