LOGARITHMIC BISOLITONS IN THE HIGH Tc SUPERCONDUCTING MATERIALS

1994 ◽  
Vol 08 (28) ◽  
pp. 1771-1779 ◽  
Author(s):  
Z. RAJILIĆ ◽  
D. MIRJANIĆ
Keyword(s):  
Crystal Lattice ◽  
High Temperature Superconductivity ◽  
Charge Carriers ◽  
Special Choice ◽  
Zero Temperature ◽  
Critical Temperatures ◽  
High Tc ◽  
One Dimensional ◽  
The One ◽  
Coherence Lengths

The one-dimensional bigausson model at zero temperature is generalized. The results of this generalization are the logarithmic soliton and logarithmic bisoliton which are, for special choice of parameters, equal to the gausson and bigausson respectively. The logarithmic bisoliton model of high temperature superconductivity explains (i) the different critical temperatures for the same crystal lattice and the same density of the charge carriers, (ii) the localization and its effect on superconductivity, (iii) the different coherence lengths for the same crystal lattice, the same density of the charge carriers, and the same T c , (iv) the complexity of the normal state, and (v) the nonstability of the anomalous high Tc superconductivity (T>150 K ).

Electron-Doped High Tc Superconductors

MRS Bulletin ◽  
1990 ◽  
Vol 15 (6) ◽  
pp. 60-67 ◽  
Author(s):  
M. Brian Maple
Keyword(s):  
High Temperature ◽  
High Temperature Superconductivity ◽  
High Temperature Superconductors ◽  
Building Blocks ◽  
The United States ◽  
Charge Carriers ◽  
Critical Temperatures ◽  
High Tc ◽  
Prevailing View ◽  
Identical Crystal

Since the discovery of high temperature superconductivity in layered copper-oxide compounds in the latter part of 1986, an enormous amount of research has been carried out on these remarkable materials. Prior to 1989, the prevailing view was that the charge carriers responsible for superconductivity in these materials were holes that move through conducting CuO2 planes. The CuO2 planes are the basic building blocks of the crystal structures of all the presently known oxides with superconducting critical temperatures Tc greater than ~30 K. Recently, new superconducting materials have been discovered in Japan and the United States in which the charge carriers involved in the superconductivity appear to be electrons, rather than holes, that reside within the conducting CuO2 planes. These findings could have important implications regarding viable theories of high temperature superconductivity as well as strategies for finding new high temperature superconductors.The new electron-doped materials have the chemical formula Ln2-xMxCuO4-y and exhibit superconductivity with superconducting critical temperatures Tc as high as ~25 K for x ≍ 0.15 and y ≍ 0.02. Superconductivity has been discovered for M = Ce and Ln = Pr, Nd, Sm, and Eu, and for M = Th and Ln = Pr, Nd, and Sm. A related compound with the identical crystal structure, Nd2CuO4-x-y Fx, has also been found to display superconductivity withTc ≍ 25 K. Recently, it has been observed that superconductivity with Tc ≍ 25 K can even be induced in nonsuperconducting Nd2-xCexCuO4-y compounds by substituting Ga or In for Cu. Thus, it appears that the CuO2 planes can be doped with electrons, rendering the Ln2CuO4-y parent compounds metallic and superconducting, by substituting electron donor elements at sites within, as well as outside, the CuO2 planes; i.e., by substituting (1) Ce4+ or Th4+ ions for Ln3+ ions; (2) F1- ions for O2- ions; and (3) Ga3+ or In3+ ions for Cu2+ ions.

scholarly journals Fractional Statistics of Charge Carriers in the One- and Two-Dimensional t-J Model: A Hint for the Cuprates?

2020 ◽  
Vol 5 (1) ◽  
pp. 12
Author(s):  
Pieralberto Marchetti
Keyword(s):  
Exact Solution ◽  
Charge Carriers ◽  
One Dimension ◽  
Two Dimensional ◽  
High Tc ◽  
One Dimensional ◽  
Similarities And Differences ◽  
Composite Nature ◽  
The One ◽  
High Tc Cuprates

We show that we can interpret the exact solution of the one-dimensional t-J model in the limit of small J in terms of charge carriers with both exchange (braid) and exclusion (Haldane) statistics with parameter 1/2. We discuss an implementation of the same statistics in the two-dimensional t-J model, emphasizing similarities and differences with respect to one dimension. In both cases, the exclusion statistics is a consequence of the no-double occupation constraint. We argue that the application of this formalism to hole-doped high Tc cuprates and the derived composite nature of the hole give a hint to grasp many unusual properties of these materials.

scholarly journals EMPTINESS FORMATION PROBABILITY AND QUANTUM KNIZHNIK-ZAMOLODCHIKOV EQUATION

2004 ◽  
Vol 19 (supp02) ◽  
pp. 57-81
Author(s):  
H. E. BOOS ◽  
V. E. KOREPIN ◽  
F. A. SMIRNOV
Keyword(s):  
Quantum Correlations ◽  
Zero Magnetic Field ◽  
Heisenberg Antiferromagnet ◽  
Zero Temperature ◽  
One Dimensional ◽  
Formation Probability ◽  
Antiferromagnetic Ground State ◽  
A New Technique ◽  
The One ◽  
Zamolodchikov Equation

We consider the one-dimensional XXX spin 1/2 Heisenberg antiferromagnet at zero temperature and zero magnetic field. We are interested in a probability of a formation of a ferromagnetic string P(n) in the antiferromagnetic ground-state. We call it emptiness formation probability [EFP]. We suggest a new technique for computation of the EFP in the inhomogeneous case. It is based on the quantum Knizhnik-Zamolodchikov equation [qKZ]. We calculate EFP for n≤6 for the inhomogeneous case. The homogeneous limit confirms our hypothesis about the relation of quantum correlations and number theory. We also make a conjecture about a structure of EFP for arbrary n.

THE ROLE OF QUASI-ONE-DIMENSIONAL STRUCTURES IN HIGH-Tc SUPERCONDUCTIVITY

1989 ◽  
Vol 03 (03) ◽  
pp. 427-439 ◽  
Author(s):  
N. M. BOGOLIUBOV ◽  
V. E. KOREPIN
Keyword(s):  
Critical Temperature ◽  
Critical Exponents ◽  
Electron Tunneling ◽  
Dimensional System ◽  
Cooper Pairs ◽  
High Tc ◽  
Mean Values ◽  
One Dimensional ◽  
The One

The critical exponents describing the decrease of correlation functions on long distances for the one-dimensional Hubbard model is obtained. The behaviour of correlators shows that Cooper pairs of electrons are formed. The electron tunneling between the chains leads to the existence of the anomalous mean values and to the superconductive current. The anisotropy of the quasi-one-dimensional system leads to the rise of critical temperature T c .

New exact results for the defective square lattice

1976 ◽  
Vol 80 (2) ◽  
pp. 365-381 ◽  
Author(s):  
G. Ronca
Keyword(s):  
Closed Form Solution ◽  
Exact Result ◽  
Form Solution ◽  
Square Lattice ◽  
Zero Temperature ◽  
Real Crystal ◽  
One Dimensional ◽  
Resonance Modes ◽  
The One ◽  
Dimensional Crystal

Since the publication of the fundamental papers by Lifshitz (1, 2) and Montroll and Potts (3, 4) many authors have investigated the effect of an isotopic impurity on the lattice vibrations of a harmonic crystal at zero temperature. A fairly broad knowledge is now available on scattering amplitudes, localized modes and resonance modes (6, 7). Nevertheless, as pointed out by Maradudin and Montroll (see (7), p. 430), a closed form solution to the problem has been found only for the one-dimensional crystal, the work done on two and three-dimensional crystals being predominantly numerical. Unfortunately the one-dimensional crystal, as an approximation for a real crystal is an oversimplified model, incapable as it is of exhibiting resonance modes. To the author's knowledge the most significant exact result concerning the classical behaviour at zero temperature of crystals having a dimensionality higher than one is the connexion, calculated by Mahanty et al. (5) between localized mode frequency and impurity mass for the case of a square lattice undergoing planar vibrations.

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