QUASIPARTICLES IN HIGH-TEMPERATURE SUPERCONDUCTORS

2003 ◽  
Vol 17 (04n06) ◽  
pp. 578-583
Author(s):  
ROBERTA CITRO ◽  
MARIA MARINARO ◽  
K. NAKAGAWA
Keyword(s):  
High Temperature ◽  
Energy Distribution ◽  
Hubbard Model ◽  
Spectral Function ◽  
Momentum Distribution ◽  
Distribution Curve ◽  
High Temperature Superconductors ◽  
Quantum Criticality ◽  
Energy Distribution Curve ◽  
Coupling Approach

We study the quantum criticality effects induced by a singular charge vertex on the quasiparticle spectral function of an extended single-band Hubbard model. It is shown that the spectral intensity computed in a strong-coupling approach, reproduces the Momentum Distribution Curve (MDC) and the Energy Distribution Curve (EDC) of ARPES experiments on Bi 2 Sr 2 CaCu 2 O 8+δ.

scholarly journals SPECTRAL ANOMALY AND HIGH TEMPERATURE SUPERCONDUCTORS

1996 ◽  
Vol 10 (07) ◽  
pp. 805-845 ◽  
Author(s):  
LAN YIN ◽  
SUDIP CHAKRAVARTY
Keyword(s):  
High Temperature ◽  
Spectral Function ◽  
Superconducting State ◽  
Fermi Liquid ◽  
Cuprate Superconductors ◽  
High Temperature Superconductors ◽  
Universality Class ◽  
Scaling Relation ◽  
Critical System ◽  
Spectral Anomaly

Spectral anomaly for interacting fermions is characterized by the spectral function A ([k − k F ], ω) satisfying the scaling relation A (Λy1 [k − k F ], Λy2 ω) =ΛyA A ([k − k F ], ω), where y1, y2, and yA are the exponents defining the universality class. For a Fermi liquid y1 = 1, y2 = 1, yA = −1; all other values of the exponents are termed anomalous. In this paper, an example for which y1 = 1, y2 = 1, but yA = α − 1 is considered in detail. Attractive interaction added to such a critical system leads to a novel superconducting state, which is explored and its relevance to high temperature cuprate superconductors is discussed.

scholarly journals The β-particle emission of radium D

1931 ◽  
Vol 133 (822) ◽  
pp. 367-380 ◽  
Keyword(s):  
Energy Distribution ◽  
Distribution Curve ◽  
Continuous Distribution ◽  
Absolute Number ◽  
Particle Emission ◽  
Low Energy ◽  
Secondary Particles ◽  
Energy Distribution Curve ◽  
Γ Ray ◽  
Number Of Particles

The main object of this investigation was to obtain an energy distribution curve for the electrons emitted by radium D during its disintegration. Such a distribution curve may be expected to be made up by the electrons coming from the nucleus, which have a continuous distribution of energy, together with secondary particles forming groups of homogeneous energy, produced by the action of the single γ-ray of radium D. The nuclear electrons are of great interest because owing to their very low energy they have never been identified with any certainty. The energy distribution finally obtained is shown in fig. 4, each point on the curve representing the number of particles having energies lying within 1000 volts on either side of the point. A secondary object of the work was to attempt to estimate the absolute number of particles emitted per disintegration, which number should, of course, be unity for the nuclear particles and some fraction less than unity for the secondary groups. The latter are due to the ejection of electrons from the L and outer atomic levels only, since the energy of the γ-ray, 47,200 volts, is insufficient to ionise the K level.

Study of correlation functions in molecular crystals

1989 ◽  
Vol 67 (11) ◽  
pp. 1036-1039
Author(s):  
M. S. Wartak ◽  
C. Y. Fong
Keyword(s):  
Correlation Function ◽  
High Temperature ◽  
Hubbard Model ◽  
Correlation Functions ◽  
Nearest Neighbor ◽  
High Temperature Superconductors ◽  
Molecular Crystals ◽  
Vibrational Properties ◽  
Model Hamiltonian

We have studied the correlation functions for a model Hamiltonian describing the vibrational properties in molecular crystals. The model Hamiltonian consists of terms characterizing the on-site anharmonicity and the nearest-neighbor hopping interaction. If the on-site anharmonicity is uniform, the correlation functions exhibit no structure. However, structure appears in the nearest-neighbor correlation function if the anharmonicity is nonuniform. Because the Hamiltonian resembles the Hubbard model for the electronic case, the implication of the results to high temperature superconductors is indicated.

Quantitative Auger and XPS Analysis of Thin Films

MRS Bulletin ◽  
1992 ◽  
Vol 17 (12) ◽  
pp. 39-45 ◽  
Author(s):  
J.M. Slaughter ◽  
W. Weber ◽  
Gernot Güntherodt ◽  
Charles M. Falco
Keyword(s):  
Thin Films ◽  
Energy Distribution ◽  
Photoelectron Spectroscopy ◽  
Distribution Curve ◽  
High Surface ◽  
Peak Height ◽  
Auger Electrons ◽  
X Ray ◽  
Surface Sensitivity ◽  
Energy Distribution Curve

In 1925, P. Auger first observed the so-called Auger electrons in a Wilson cloud chamber. He explained this occurrence as being due to a radiationless transition in atoms excited by a primary x-ray photon source. In 1953, Lander first pointed out that Auger electrons arising from solid samples can be detected in the energy distribution curve of secondary electrons from surfaces subjected to electron bombardment. Moreover, low-energy Auger electrons (∼1 keV kinetic energy) can escape from only the first several atomic layers of a surface since they are strongly absorbed by even a monolayer of atoms. Thus Auger electron spectroscopy (AES) possesses high surface sensitivity. This is one characteristic that makes AES very useful for the study of thin films. For such applications, an important development in AES occurred when Harris showed that the sensitivity of the detection of Auger electrons can be improved by differentiating the electron energy distribution curve with respect to the energy. Furthermore, Weber and Johnson demonstrated that, provided the Auger line profile does not change, the peak-to-peak height in the differentiated energy distribution curves is proportional to the Auger current in the peak. Therefore, in addition to its surface sensitivity, AES also can be used for quantitative studies of thin films.Like AES, x-ray photoelectron spectroscopy (XPS) is a surface-sensitive technique that uses the energy distribution of electrons ejected from a thin film for quantitative analysis. However, in many ways the information provided by AES and XPS is complementary.

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