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.

TRANSITION FREQUENCY OF STRONG-COUPLING IMPURITY BOUND POLARON IN AN ASYMMETRIC QUANTUM DOT

2012 ◽  
Vol 11 (03) ◽  
pp. 1250026 ◽  
Author(s):  
CHENG-SHUN WANG ◽  
YU-FANG CHEN ◽  
JING-JIN XIAO
Keyword(s):  
Excited State ◽  
Coupling Strength ◽  
State Energy ◽  
Transition Frequency ◽  
Phonon Coupling ◽  
Excited State Energy ◽  
Bound Polaron ◽  
Asymmetric Quantum Dot ◽  
Asymmetric Quantum ◽  
Electron Phonon Coupling

Properties of the excited state of strong-coupling impurity bound polaron in an asymmetric quantum dot are studied by using linear combination operator and unitary transformation methods. The first internal excited state energy, the excitation energy and the transition frequency between the first internal excited and the ground states of the impurity bound polaron as functions of the transverse and the longitudinal effective confinement lengths of the dot, the electron–phonon coupling strength and the Coulomb bound potential were derived. Our numerical results show that they will increase with decreasing the effective confinement lengths, due to interesting quantum size confining effects. But they are an increasing functions of the Coulomb bound potential. The first internal excited state energy is a decreasing function of the electron–phonon coupling strength whereas the transition frequency and the excitation energy are an increasing one of the electron–phonon coupling strength.

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).

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.

EFFECTS OF ANISOTROPIC PARABOLIC POTENTIAL ON THE ENERGY LEVELS AND TRANSITION FREQUENCY OF STRONG-COUPLING POLARON IN A QUANTUM DOT

2013 ◽  
Vol 12 (03) ◽  
pp. 1350016 ◽  
Author(s):  
CHUN-YU CAI ◽  
CUI-LAN ZHAO ◽  
JING-LIN XIAO
Keyword(s):  
Quantum Dot ◽  
Strong Coupling ◽  
Coupling Strength ◽  
Energy Levels ◽  
Three Dimensional ◽  
Transformation Method ◽  
Transition Frequency ◽  
Quantum Size ◽  
Parabolic Potential ◽  
Confining Effect

In the presence of a three-dimensional anisotropic parabolic potential (APP), the energy levels and the transition frequency between relevant levels of the strong-coupling polaron in a quantum dot (QD) are investigated by using the well-known Lee-Low-Pines (LLP) unitary transformation method and the Pekar type variational (PTV) method. The relations of the energy levels and the transition frequency with the electron–phonon (EP) coupling strength and the effective confinement lengths are derived. Numerical calculations show that the energy levels are decreasing functions of the EP coupling strength, whereas the transition frequency is an increasing one of it. And they are all increasing rapidly with decreasing the effective confinement lengths in different directions, which are showing the novel quantum size confining effect of the QD.

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