Metal insulator transition due to surface roughness scattering in a quantum well

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.

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Metal–insulator transition in a quantum well under the influence of electric field

Physica B Condensed Matter ◽

10.1016/j.physb.2005.05.031 ◽

2005 ◽

Vol 366 (1-4) ◽

pp. 146-152 ◽

Cited By ~ 15

Author(s):

A. John Peter ◽

K. Navaneethakrishnan

Keyword(s):

Electric Field ◽

Quantum Well ◽

Insulator Transition ◽

Metal Insulator Transition ◽

Metal Insulator

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

International Journal of Nanoscience ◽

10.1142/s0219581x08005341 ◽

2008 ◽

Vol 07 (04n05) ◽

pp. 207-213 ◽

Cited By ~ 1

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.

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