scholarly journals Metal-insulator transition in disordered systems from the one-body density matrix

2017 ◽  
Vol 95 (4) ◽  
Author(s):  
Thomas Olsen ◽  
Raffaele Resta ◽  
Ivo Souza
Keyword(s):  
Density Matrix ◽  
Disordered Systems ◽  
Insulator Transition ◽  
Body Density ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
The One

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.

METAL–INSULATOR TRANSITION AND THE TEMPERATURE OF THE PSEUDOGAP ANOMALY OPENING IN PRASEODYMIUM DOPED Y1-zPrzBa2Cu3O7-δ SINGLE CRYSTALS

2013 ◽  
Vol 27 (04) ◽  
pp. 1350029 ◽  
Author(s):  
R. V. VOVK ◽  
Z. F. NAZYROV ◽  
I. L. GOULATIS ◽  
A. CHRONEOS ◽  
V. M. PINTO SIMOES
Keyword(s):  
Electrical Resistivity ◽  
Single Crystals ◽  
Insulator Transition ◽  
Critical Regime ◽  
Significant Shift ◽  
Asymptotic Dependence ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
The One ◽  
Praseodymium Doping

The influence of praseodymium doping on the electrical resistivity in the ab-plane of Y 1-z Pr z Ba 2 Cu 3 O 7-δ single crystals, is investigated. It is determined that as the concentration of praseodymium (0.0 ≤ z ≤ 0.5) is rising there occurs a significant shift of the temperature regions, corresponding to the metal–insulator transitions, as well as to the regime of the implementation of the pseudogap anomaly. The part of the curves related to the metal–insulator transition are well described by means of an asymptotic dependence that corresponds to the implementation of a quantum critical regime in the system, the so-called law of the "one third".

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