Effects of dielectric screening and position dependent effective mass on donor binding energies and on diamagnetic susceptibility in a quantum well

2008 ◽  
Vol 43 (3) ◽  
pp. 247-261 ◽  
Author(s):  
S. Rajashabala ◽  
K. Navaneethakrishnan
Keyword(s):  
Quantum Well ◽  
Effective Mass ◽  
Diamagnetic Susceptibility ◽  
Binding Energies ◽  
Dielectric Screening

EFFECT OF DIELECTRIC SCREENING ON THE DIAMAGNETIC SUSCEPTIBILITY OF A DONOR IN LOW DIMENSIONAL SEMICONDUCTING SYSTEMS

2009 ◽  
Vol 23 (08) ◽  
pp. 2069-2075
Author(s):  
P. NITHIANANTHI ◽  
P. VICKRAMAN ◽  
K. JAYAKUMAR
Keyword(s):  
Quantum Dot ◽  
Variational Method ◽  
Quantum Well ◽  
Effective Mass ◽  
Diamagnetic Susceptibility ◽  
Quantum Well Wire ◽  
Dielectric Screening ◽  
Low Dimensional ◽  
Infinite Barrier ◽  
Barrier Model

The effect of spatial dielectric screening on the diamagnetic susceptibility (χ dia ) of a donor in Low Dimensional Semiconducting Systems like Quantum Well, Quantum Well Wire and Quantum Dot in the infinite barrier model has been computed and investigated within the effective mass theory using variational method. We observe that the effect of spatial dielectric screening on χ dia decreases with decrease of dimensionality of the system.

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.

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.

EFFECTIVE MASSES FOR DONOR BINDING ENERGIES IN QUANTUM WELL SYSTEMS

2006 ◽  
Vol 20 (24) ◽  
pp. 1529-1541 ◽  
Author(s):  
S. RAJASHABALA ◽  
K. NAVANEETHAKRISHNAN
Keyword(s):  
Quantum Well ◽  
Effective Mass ◽  
Binding Energies ◽  
Bohr Radius ◽  
Mass Variation ◽  
Effective Masses ◽  
Approximate Form ◽  
Finite Barrier ◽  
Infinite Barrier ◽  
Barrier Model

The donor ionization energies in a quantum well and quantum dot with finite and infinite barriers are estimated for different well dimensions. Using the effective mass (EM) approximation, calculations are presented with constant effective mass and position dependent effective masses that are different for finite and infinite cases. Our results reduce to an approximate form used by X. H. Qi et al., Phys. Rev. B58 (1998) 10578 in the finite barrier model and that of L. E. Oliveira and L. M. Falicov, Phys. Rev. B34 (1986) 8676 in the infinite barrier case. Results are presented by taking the GaAs quantum well as an example. The use of constant effective mass of 0.067m0 is justified for well dimensions ≥a* where a* is an effective Bohr radius which is about 100 Å. While Qi et al. found a maximum of 22% variation in the binding energies due to mass variation, we obtained nearly 100% variation when mass variations are included correctly.

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.

Simultaneous effects of pressure and temperature on excitons in Pöschl–Teller quantum well

2017 ◽  
Vol 31 (08) ◽  
pp. 1750050 ◽  
Author(s):  
A. Anitha ◽  
M. Arulmozhi
Keyword(s):  
Binding Energy ◽  
Quantum Well ◽  
Effective Mass ◽  
Heavy Hole ◽  
Light Hole ◽  
Binding Energies ◽  
Exciton Binding Energy ◽  
Effective Mass Approximation ◽  
Mass Approximation ◽  
Asymmetric Configuration

Binding energies of the heavy hole and light hole exciton in a quantum well with Pöschl–Teller (PT) potential composed of GaAs have been studied variationally within effective mass approximation. The effects of pressure and temperature on exciton binding energy are analyzed individually and also simultaneously for symmetric and asymmetric configuration of the well. The results show that exciton binding energy (i) decreases as the well width increases, (ii) increases with pressure and (iii) decreases with temperature. Simultaneous effects of these perturbations lead to more binding of the exciton. The results are compared with the existing literature.

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