Electronic density of states for two-dimensional system in uniform magnetic and Aharonov–Bohm fields

2011 ◽  
Vol 37 (11) ◽  
pp. 940-946
Author(s):  
A. O. Slobodeniuk ◽  
S. G. Sharapov ◽  
V. M. Loktev
Keyword(s):  
Density Of States ◽  
Dimensional System ◽  
Two Dimensional ◽  
Electronic Density ◽  
Electronic Density Of States ◽  
Two Dimensional System ◽  
Aharonov Bohm

A Modified Extended Hückel Calculations For Q1D-Graphites

1990 ◽  
Vol 214 ◽  
Author(s):  
D. Raković ◽  
R. Kostić ◽  
S. Krstić ◽  
I. Davidova ◽  
B. L. Fayfel ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Density Of States ◽  
Computational Results ◽  
Two Dimensional ◽  
Electronic Density ◽  
Electronic Density Of States ◽  
Energy Gaps ◽  
Extended Hückel ◽  
Extended Hückel Calculations

ABSTRACTIn this paper we have computed electronic density of states for several Q1D graphites: polyacene (PA), polyacenacene (PAA), polyphenanthrene (PP), polyphenanthrophenanthrene (PPhP), and polyperinaphthalene (PPN). The modified extended Hiickel method for finite Q1D chains has been adopted. The change of the electronic properties due to the growth of the Q1D-graphites toward the two-dimensional direction, starting from trans-polyacetylene, cis-polyacetylene or poly(p-phenylene), is discussed. Our calculations show that PA, PAA, and PPN are intrinsic conductors, while PP and PPh are semiconductors with energy gaps of 1,4 eV and 0,8 eV, respectively. The comparison with other computational results is presented.

Localization and interaction effects in weakly disordered two-dimensional systems

1982 ◽  
Vol 60 (5) ◽  
pp. 746-756 ◽  
Author(s):  
Moshe Kaveh
Keyword(s):  
Thin Film ◽  
Density Of States ◽  
Hall Coefficient ◽  
Electronic States ◽  
Dimensional System ◽  
Two Dimensional ◽  
Theoretical Approaches ◽  
Two Dimensional System ◽  
Interaction Approach ◽  
Localization Approach

The question of whether a two-dimensional metal can exist is discussed. The theoretical and experimental position is reviewed. Experimentally, the conductivity of a two-dimensional system (such as inversion layers or thin film metals) shows the following nonmetallic behavior: (i) logarithmic decrease of the conductivity as T → 0. (ii) negative magnetoresistance, (iii) logarithmic decrease of the Hall coefficient as T → 0, and (iv) nonohmic conductivity, increasing logarithmically with electric field.The nonmetallic behavior of the conductivity is discussed in view of two recent theoretical approaches, (i) The localization approach, which predicts that all electronic states in a two-dimensional system are localized, and (ii) the interaction approach which predicts a logarithmic decrease in the density of states as the temperature is decreased.Evidence for both theories is presented.

ON THE DENSITY OF ELECTRONIC STATES OF TWO-DIMENSIONAL POSITIONALLY DISORDERED SYSTEMS WITH WEAK ELECTRON-ION POTENTIAL

1987 ◽  
Vol 01 (05n06) ◽  
pp. 1321-1328 ◽  
Author(s):  
K.V. BHAGWAT ◽  
S.V. LAWANDE ◽  
D.C. KHANDEKAR
Keyword(s):  
Density Of States ◽  
Disordered Systems ◽  
Gaussian Model ◽  
Dimensional System ◽  
Two Dimensional ◽  
Tail Region ◽  
Disordered System ◽  
Electronic Density ◽  
Average Electron ◽  
Weak Electron

The path-integral formulation of Edwards and Gulyaev has been used to investigate the behaviour of electronic density of states in the two-dimensional positionally disordered systems. The average electron propagator is evaluated within the first cumulant approximation. It is shown that in general the two-dimensional system possesses a non-zero density of states in the band-tail region. In particular an expression for the density of states for a Gaussian model of a two-dimensional disordered system is derived. Numerical values of density of states for this model for some typical values of parameters are also given.

EXCITON BOUND TO MAGNETIC IMPURITIES IN TWO DIMENSION SYSTEMS UNDER STRONG MAGNETIC FIELD

2007 ◽  
Vol 21 (08n09) ◽  
pp. 1460-1465
Author(s):  
PINCHAS DAHAN
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Strong Magnetic Field ◽  
Density Of States ◽  
Dimensional System ◽  
Magnetic Impurities ◽  
Two Dimensional ◽  
Van Hove Singularity ◽  
Deep Impurity ◽  
Two Dimensional System

The possibility of excitons bound to magnetic impurities in a two-dimensional system quantized by a strong magnetic field is considered. We show that the Landau quantization leads to dramatic changes in the structure of these bound excitons. Such changes are due primarily to a lower symmetry, which lifts the selection rules in the hybridization integrals, and in turn leads to a threshold van Hove singularity of the density of states in a two-dimensional system. Hence, a bound exciton with zero angular momentum, m = 0, is captured by a spin selective potential of the deep impurity levels.

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