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The study of some physical properties of high temperature superconductors

Abstract

The phenomenon of superconductivity, the discovery of high temperature superconductivity in the Cuprates and the properties of these materials is described in the introductory chapter. It also includes a discussion of the pseudogap, which has remained a mystery as has the high transition temperature. Possible applications of high temperature superconductivity are reviewed before the theories by Bardeen, Cooper, and Schrieffer (BCS) and Ginzburg and Landau are briefly sketched. The last section gives excerpts of the by now vast literature on this subject, focussing on the role impurities play in this context. The second chapter develops the mathematical tools and the theoretical background for the description of many-body systems. Various Green's functions are introduced which are then used to describe scattering of quasiparticles off defects of arbitrary strength. They are also required to calculate the a.c. conductivity, for which an expression is derived using linear response theory. The convergence problems one encounters when actually calculating the conductivity are briefly discussed. Detailed calculations for the normal state are presented in the third chapter and in the appendix. The third Chapter begins with a detailed presentation of the tight binding model for the energy dispersion because this model appears to give a more  More>>
Publication Date:
Jul 01, 2008
Product Type:
Thesis/Dissertation
Report Number:
INIS-DE-0530
Resource Relation:
Other Information: TH: Diss.
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; SUPERCONDUCTIVITY; CUPRATES; TRANSITION TEMPERATURE; SCATTERING; CONVERGENCE; FERMI LEVEL; INTEGRALS; DOPED MATERIALS; HOLES; HIGH-TC SUPERCONDUCTORS; QUASI PARTICLES; BOUND STATE; PROGRESS REPORT; BCS THEORY; MANY-BODY PROBLEM; GREEN FUNCTION; DISPERSION RELATIONS; ELECTRONIC STRUCTURE; BAND THEORY; ENERGY-LEVEL DENSITY; HILBERT TRANSFORMATION; CRYSTAL MODELS; ENERGY GAP; D WAVES; SECOND QUANTIZATION; FOURIER TRANSFORMATION
OSTI ID:
21125840
Research Organizations:
Hamburg Univ. (Germany). Fachbereich 12 - Physik
Country of Origin:
Germany
Language:
English
Other Identifying Numbers:
TRN: DE09F0500
Availability:
Commercial reproduction prohibited; INIS; OSTI as DE21125840
Submitting Site:
DEN
Size:
143 pages
Announcement Date:
Feb 26, 2009

Citation Formats

Ismail, Atif Mahmoud. The study of some physical properties of high temperature superconductors. Germany: N. p., 2008. Web.
Ismail, Atif Mahmoud. The study of some physical properties of high temperature superconductors. Germany.
Ismail, Atif Mahmoud. 2008. "The study of some physical properties of high temperature superconductors." Germany.
@misc{etde_21125840,
title = {The study of some physical properties of high temperature superconductors}
author = {Ismail, Atif Mahmoud}
abstractNote = {The phenomenon of superconductivity, the discovery of high temperature superconductivity in the Cuprates and the properties of these materials is described in the introductory chapter. It also includes a discussion of the pseudogap, which has remained a mystery as has the high transition temperature. Possible applications of high temperature superconductivity are reviewed before the theories by Bardeen, Cooper, and Schrieffer (BCS) and Ginzburg and Landau are briefly sketched. The last section gives excerpts of the by now vast literature on this subject, focussing on the role impurities play in this context. The second chapter develops the mathematical tools and the theoretical background for the description of many-body systems. Various Green's functions are introduced which are then used to describe scattering of quasiparticles off defects of arbitrary strength. They are also required to calculate the a.c. conductivity, for which an expression is derived using linear response theory. The convergence problems one encounters when actually calculating the conductivity are briefly discussed. Detailed calculations for the normal state are presented in the third chapter and in the appendix. The third Chapter begins with a detailed presentation of the tight binding model for the energy dispersion because this model appears to give a more accurate description of the electronic properties of high temperature superconductors than the nearly free electron model. The shape of the two-dimensional Fermi surface is calculated and displayed as function of band filling and the next-nearest neighbor hopping integral B, assuming a rigid band. B plays an important role in the formation of so-called hot spots. The quasiparticle density of states and its Hilbert transform F({omega}) are solved by means of complete elliptic integrals formalism. These results are used to obtain impurity bound states. A simple model for the superconductivity in the cuprate materials is developed on the basis of hot spots and the pseudogap, particularly relevant for the electron doped materials, where electrons and holes might coexist, depending on the degree of doping. (orig.).}
place = {Germany}
year = {2008}
month = {Jul}
}