Electronic Structure and Transport in Non Periodic Systems: New O(N) Methods

1997 ◽  
Vol 491 ◽  
Author(s):  
D. Mayou ◽  
P. E. A. Turchi ◽  
S. Roche ◽  
J. P. Julien
Keyword(s):  
Linear Response ◽  
Mathematical Theory ◽  
Tight Binding ◽  
Mean Field ◽  
Real Space ◽  
The Self ◽  
Field Theories ◽  
Periodic Systems ◽  
New Approach ◽  
Self Consistent

ABSTRACTThe mathematical theory of orthogonal polynomials and continued fractions provides efficient tools, via the recursion and related methods, for calculating diagonal elements of Green's function of tight-binding Hamiltonians. We present two recent generalizations of this formalism. The first one allows the calculation of conductivity and other linear response coefficients. The second one provides a new approach to the solution of mean-field theories of alloys. In particular it is shown that the self-consistent CPA equations can be easily solved, through a real-space calculation, for multi-component alloys based on periodic or non periodic lattices.

Linear response in stochastic mean-field theories and the onset of instabilities

1994 ◽  
Vol 567 (3) ◽  
pp. 637-654 ◽  
Author(s):  
M. Colonna ◽  
Ph. Chomaz ◽  
J. Randrup
Keyword(s):  
Linear Response ◽  
Mean Field ◽  
Field Theories ◽  
Mean Field Theories

New Tight-Binding Method for Simulation of Defect Configurations, Creation and Diffusion Mechanisms in Solids: Application to Silicon

1998 ◽  
Vol 527 ◽  
Author(s):  
Zokirkhon M. Khakimov
Keyword(s):  
Tight Binding ◽  
The Self ◽  
Atomic Diffusion ◽  
Self Consistent ◽  
Tight Binding Method ◽  
Comparable Accuracy ◽  
Diffusion Mechanisms ◽  
New Generation ◽  
And Diffusion ◽  
Metastable Defect

ABSTRACTThis paper presents the self-consistent tight-binding method of new generation which, unlike other tight-binding methods, allows one to calculate structural energies of multiatomic systems (molecules, clusters, defects in solids) and their spectroscopic energies in the framework of the same computational scheme and with comparable accuracy. Reliability of the method is illustrated considering defect state problems in crystalline and amorphous silicon (electron-enhanced-atomic diffusion, metastable defect creation, defects with effective-negative correlation energies, etc.) and comparing obtained results with ab initio calculations and experimental data.

Tight-Binding Study of the {211} Σ=3 Grain Boundary in Cubic Silicon-Carbide

1994 ◽  
Vol 339 ◽  
Author(s):  
M. Kohyama ◽  
R. Yamamoto
Keyword(s):  
Grain Boundaries ◽  
Electronic Structures ◽  
Tight Binding ◽  
The Self ◽  
Localized States ◽  
General Definition ◽  
Self Consistent ◽  
Tight Binding Method ◽  
Definition Of ◽  
Cubic Silicon Carbide

ABSTRACTIn grain boundaries in compound semiconductors such as SiC, the interface stoichiometry and the wrong bonds between like atoms are of much importance. Firstly, a general definition of the interface stoichiometry in such grain boundaries has been discussed. Secondly, the atomic and electronic structures of the {211} Σ=3 boundary in SiC have been examined by using the self-consistent tight-binding method, based on the atomic models with bonding networks similar to those in the models of the same boundary in Si or Ge. The wrong bonds have significant effects through the large electrostatic repulsion and the generation of localized states as well as those in the {122} Σ=9 boundary in SiC. And the different bond lengths of the wrong bonds very much affect the local bond distortions at the interfaces, which determines the relative stability among the present models.

New Tight-Binding Method for Simulation of Defect Configurations, Creation and Diffusion Mechanisms in Solids: Application to Silicon

1998 ◽  
Vol 532 ◽  
Author(s):  
Zokirkhon M. Khakimov
Keyword(s):  
Tight Binding ◽  
The Self ◽  
Atomic Diffusion ◽  
Self Consistent ◽  
Tight Binding Method ◽  
Comparable Accuracy ◽  
Diffusion Mechanisms ◽  
New Generation ◽  
And Diffusion ◽  
Metastable Defect

ABSTRACTThis paper presents the self-consistent tight-binding method of new generation which, unlike other tight-binding methods, allows one to calculate structural energies of multiatomic systems (molecules, clusters, defects in solids) and their spectroscopic energies in the framework of the same computational scheme and with comparable accuracy. Reliability of the method is illustrated considering defect state problems in crystalline and amorphous silicon (electronenhanced- atomic diffusion, metastable defect creation, defects with effective-negative correlation energies, etc.) and comparing obtained results with ab initio calculations and experimental data.

THE PROBLEM OF UNIVERSALITY OF NUCLEAR MEAN-FIELD PARAMETRIZATIONS

2005 ◽  
Vol 14 (03) ◽  
pp. 493-498 ◽  
Author(s):  
NOËL DUBRAY ◽  
JERZY DUDEK ◽  
NICOLAS SCHUNCK
Keyword(s):  
Mean Field ◽  
Exotic Nuclei ◽  
Phenomenological Description ◽  
Field Theories ◽  
Hartree Fock ◽  
Relativistic Mean Field ◽  
Self Consistent ◽  
Mean Field Theories

Most of the microscopic self-consistent approaches such as Hartree-Fock and/or Relativistic Mean Field theories use ensembles of a few adjustable parameters that are independent of the proton and neutron numbers and fixed once for all. This feature is referred to as the universality of the parametrization. It is further developed for the case of the phenomenological description of the nuclear deformed mean-field e.g. in the Woods-Saxon form and discussed in view of obtaining the parametrizations that are most stable with respect to extrapolations for the unknown nuclear ranges as e.g. in the case of various groups exotic nuclei. A new universal parametrization is obtained and an illustration presented.

The behaviors of the solutions of the quark gap equation in the NJL model with the self-consistent mean field approximation

2021 ◽  
Author(s):  
Zu-Qing Wu ◽  
Jia-Lun Ping ◽  
Hong-Shi Zong
Keyword(s):  
Chiral Limit ◽  
Mean Field ◽  
Stable Solution ◽  
Field Approximation ◽  
The Self ◽  
Mean Field Approximation ◽  
Chiral Phase ◽  
Gap Equation ◽  
Self Consistent ◽  
Exchange Channel

In this paper, we use the self-consistent mean field approximation to study the Quantum Chromodynamics (QCD) phase transition. In the self-consistent mean field approximation of the Nambu–Jona-Lasinio (NJL) model, a parameter [Formula: see text] is introduced, which reflects the weight of “direct” channel and the “exchange” channel and needs to be determined by experiments (as mentioned in a recent work [T. Zhao, W. Zheng, F. Wang, C.-M. Li, Y. Yan, Y.-F. Huang and H.-S. Zong, Phys. Rev. D 100, 043018 (2019)], the results with [Formula: see text] are in good agreement with astronomical observation data on the latest binary neutron star merging. This indicates that the contribution of “exchange” channel should be considered, and [Formula: see text] is a possible choice). By comparing the results with different parameter [Formula: see text]’s ([Formula: see text], [Formula: see text] and [Formula: see text]), we study the influence of “exchange” channel on the behavior of the solutions of the quark gap equation and the critical point of chiral phase transition. Our results show that the second-order chiral phase turns to the crossover from the chiral limit to the non-chiral limit around [Formula: see text] in the case of [Formula: see text]. The difference of the quark mass with different [Formula: see text]’s mainly occurs in the intermediate temperatures for the different fixed chemical potentials. At zero temperature and the chemical potential [Formula: see text] there will be two solutions (including a meta-stable solution) of gap equation with [Formula: see text], and as [Formula: see text] increases it will be only one solution left (the meta-stable solution will disappear until [Formula: see text]). Besides, the discrepancy of the critical temperature (above which the pseudo-Wigner solution and negative Nambu solution will disappear) in the three cases of [Formula: see text] will become large when the chemical potential increases.

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