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.

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.

scholarly journals Polaronic Effects of a Hydrogenic Donor Impurity in Low Dimensional Semiconductor Systems

2009 ◽  
Vol 1 (3) ◽  
pp. 422-429 ◽  
Author(s):  
A. J. Peter ◽  
N. Radhakrishnan
Keyword(s):  
Binding Energy ◽  
Quantum Dot ◽  
Quantum Well ◽  
Longitudinal Optical ◽  
Wire Radius ◽  
Donor Impurity ◽  
Donor Binding Energy ◽  
Quantum Well Wire ◽  
Hydrogenic Donor ◽  
Low Dimensional

The ground state of a polaron bound to hydrogen like donor impurity is investigated by considering the effect of bulk Longitudinal-Optical (LO) phonon. Donor binding energy of a hydrogenic donor, with the inclusion of electron-phonon interaction is computed for the low-dimensional semiconducting systems like quantum well, quantum well wire and quantum dot taking GaAs/AlxGa1-xAs systems as an example. Calculations are performed using a variational approach within the single band effective mass approximation. The results show that the polaronic effect is more pronounced for the lowest confinement. The polaronic effect enhances the donor binding energy but it diminishes when the well width, wire radius and dot radius become larger. Also the numerical calculations reveal that the influences of phonons on donor are considerable and should not be neglected especially for narrow dimensions in all the three confinements.Keywords: Donor binding energy; Polaronic effect; Quantum dot; Quantum wire; Quantum well.© 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved.DOI: 10.3329/jsr.v1i3.2529            J. Sci. Res. 1 (3), 422- 429 (2009)

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   

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