INFLUENCE OF PRESSURE ON THE DIAMAGNETIC SUSCEPTIBILITY OF HYDROGENIC DONOR IN SOME LOW-LYING EXCITED STATES IN A QUANTUM WELL

2007 ◽  
Vol 06 (01) ◽  
pp. 37-40 ◽  
Author(s):  
P. NITHIANANTHI ◽  
K. JAYAKUMAR
Keyword(s):  
Hydrostatic Pressure ◽  
Quantum Well ◽  
Effective Mass ◽  
Excited States ◽  
Diamagnetic Susceptibility ◽  
Mass Approximation ◽  
X Band ◽  
Hydrogenic Donor ◽  
Band Mixing ◽  
Band Crossing

The influence of Γ–X band crossing due to the applied hydrostatic pressure on the diamagnetic susceptibility (χ dia ) of a donor in low-lying excited states like 2s, 2p0, 2p± in a GaAs / Al x Ga 1-x As Quantum Well has been investigated in the effective mass approximation by considering the nonparabolicity of the conduction band. We notice that the effect of Γ–X band mixing is significant on χ dia of a donor lying in excited states. Moreover, the effect of non-parabolicity on χ dia is also predominant for lower well width region. The results are presented and discussed.

THE EFFECTS OF TEMPERATURE AND HYDROSTATIC PRESSURE ON THE DIAMAGNETIC SUSCEPTIBILITY OF A DONOR IN A QUANTUM WELL

2011 ◽  
Vol 18 (05) ◽  
pp. 147-152 ◽  
Author(s):  
U. YESILGUL ◽  
F. UNGAN ◽  
E. KASAPOGLU ◽  
H. SARI ◽  
I. SÖKMEN
Keyword(s):  
Hydrostatic Pressure ◽  
Binding Energy ◽  
Quantum Well ◽  
Effective Mass ◽  
Diamagnetic Susceptibility ◽  
Effective Mass Approximation ◽  
Mass Approximation ◽  
Hydrogenic Donor ◽  
Different Temperatures ◽  
Effects Of Temperature

Using the effective-mass approximation within a variational scheme, we have calculated the diamagnetic susceptibility and binding energy of a hydrogenic donor in a quantum well under different temperatures and hydrostatic pressure conditions. Our calculation have revealed the dependence of the diamagnetic susceptibility and the impurity binding on temperature and hydrostatic pressure.

MAGNETIC STUDIES OF METAL–INSULATOR TRANSITION IN A QUANTUM WELL SYSTEM

2008 ◽  
Vol 07 (04n05) ◽  
pp. 207-213 ◽  
Author(s):  
A. JOHN PETER ◽  
L. CAROLINE SUGIRTHAM
Keyword(s):  
Magnetic Field ◽  
Quantum Well ◽  
Effective Mass ◽  
Diamagnetic Susceptibility ◽  
Insulator Transition ◽  
Magnetic Studies ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Intense Magnetic Field ◽  
Mass Approximation

Metal–insulator transition in doped semiconductors is investigated in the presence of intense magnetic fields. A variational procedure within the effective mass approximation is employed using the Thomas–Fermi screening function and the exact quasi-Q2D Lindhard dielectric function. The Hubbard model results are justified using an effective mass that depends on interimpurity separation. The nonparabolicity of the subband is included using an energy-dependent effective mass. Though an increase of ionization energy with a magnetic field is observed for isolated donor models, the metallization occurs with an intense magnetic field at a higher concentration for a particular well width. The diamagnetic susceptibility of a hydrogenic donor impurity in GaAs / Ga 1 - x Al x As quantum well systems is discovered in the observation of metal–insulator transition. It is shown that the diamagnetic susceptibility diverges for all critical concentrations for a given well width. The large diamagnetic susceptibility (> 6) is observed at the transition. All the calculations are carried out for infinite and finite barriers, and the results are compared with the existing literature.

scholarly journals Diamagnetic Susceptibility of a Confined Donor in a Quantum Dot with Different Confinements

2009 ◽  
Vol 1 (2) ◽  
pp. 200-208 ◽  
Author(s):  
A. J. Peter ◽  
J. Ebenezar
Keyword(s):  
Quantum Dot ◽  
Quantum Well ◽  
Harmonic Oscillator ◽  
Diamagnetic Susceptibility ◽  
Binding Energies ◽  
Hydrogenic Impurity ◽  
Mass Approximation ◽  
Quantum Well Wire ◽  
Hydrogenic Donor ◽  
System Geometry

The binding energies of shallow hydrogenic impurity in a GaAs/GaAlAs quantum dot with spherical confinement, harmonic oscillator-like and rectangular well-like potentials are calculated as a function of dot radius using a variational procedure within the effective mass approximation. The calculations of the binding energy of the donor impurity as a function of the system geometry have been investigated. A comparison of the eigenstates of a hydrogenic impurity in all the confinements of dots is discussed in detail.  We have computed and compared the susceptibility for a hydrogenic donor in a spherical confinement, harmonic oscillator-like and rectangular well-like potentials for a finite QD and observe a strong influence of the shape of confining potential and geometry of the dot on the susceptibility. Keywords: Quantum dot; Quantum well wire; Quantum well; Diamagnetic susceptibility; Donor impurity. © 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i2.1184   

Effect of geometry on the pressure induced donor binding energy in semiconductor nanostructures

2015 ◽  
Vol 04 (03) ◽  
pp. 1550018
Author(s):  
P. Kalpana ◽  
K. Jayakumar ◽  
P. Nithiananthi
Keyword(s):  
Binding Energy ◽  
External Pressure ◽  
Semiconductor Nanostructures ◽  
Mass Approximation ◽  
Hydrogenic Donor Impurity ◽  
Donor Binding Energy ◽  
X Band ◽  
Hydrogenic Donor ◽  
Band Mixing ◽  
Geometrical Effects

The effect of geometry on an on-center hydrogenic donor impurity in a GaAs /( Ga,Al ) As quantum wire (QWW) and quantum dot (QD) under the influence of Γ–X band mixing due to an applied hydrostatic pressure is theoretically studied. Numerical calculations are performed in an effective mass approximation. The ground state impurity energy is obtained by variational procedure. Both the effects of pressure and geometry are to exert an additional confinement on the impurity inside the wire as well as dot. We found that the donor binding energy is modified by the geometrical effects as well as by the confining potential when it is subjected to external pressure. The results are presented and discussed.

THE EFFECT OF HYDROSTATIC PRESSURE ON METAL–INSULATOR TRANSITION IN QUANTUM WELL SEMICONDUCTOR SYSTEMS II

2005 ◽  
Vol 04 (01) ◽  
pp. 45-53 ◽  
Author(s):  
A. JOHN PETER
Keyword(s):  
Hydrostatic Pressure ◽  
Quantum Well ◽  
Ionization Energy ◽  
Critical Concentration ◽  
Shallow Donor ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Mass Approximation ◽  
The One

Using a variational procedure within the effective mass approximation, the ionization energies of a shallow donor in a quantum well (QW) of GaAs/Ga 1-x Al x As superlattice system under the influence of pressure with the exact dielectric function are obtained. The vanishing of ionization energy initiating Mott transition is observed within the one-electron approximation. The effects of Anderson localization using a simple model, and exchange and correlation in the Hubbard model are included in this model. It is found that the ionization energy (i) increases when well width increases for a given pressure, (ii) decreases and reaches a bulk value for a larger well width, (iii) increases with increasing external hydrostatic pressure for a given QW thickness, and (iv) the critical concentration at which the metal–insulator transition (MIT) occurs is increased when pressure is applied. It also is demonstrated that MIT is not possible in a hydrostatic pressure in a quantum well supporting scaling theory of localization. All the calculations have been carried out with finite and infinite barriers and the results are compared with available data in the literature.

Low-lying excited states of a hydrogenic donor and resonant states in a quantum well

1986 ◽  
Vol 34 (12) ◽  
pp. 8794-8799 ◽  
Author(s):  
K. Jayakumar ◽  
S. Balasubramanian ◽  
M. Tomak
Keyword(s):  
Quantum Well ◽  
Excited States ◽  
Resonant States ◽  
Hydrogenic Donor
Sign in / Sign up

Export Citation Format

Share Document