scholarly journals Doping Evolution of the Electron–Hole Asymmetric s-Wave Pseudogap in Underdoped High-Tc Cuprate Superconductors

2014 ◽  
Author(s):  
Shiro Sakai ◽  
Marcello Civelli
Keyword(s):  
Cuprate Superconductors ◽  
S Wave ◽  
Electron Hole ◽  
High Tc

scholarly journals ELECTRONIC BOUND STATES IN PARITY-PRESERVING QED3 APPLIED TO HIGH-Tc CUPRATE SUPERCONDUCTORS

2003 ◽  
Vol 18 (05) ◽  
pp. 725-741 ◽  
Author(s):  
H. R. CHRISTIANSEN ◽  
O. M. DEL CIMA ◽  
M. M. FERREIRA ◽  
J. A. HELAYËL-NETO
Keyword(s):  
Bound States ◽  
Cuprate Superconductors ◽  
Energy Scale ◽  
Spontaneous Breaking ◽  
Electron Interaction ◽  
Oxide Superconductors ◽  
S Wave ◽  
High Tc ◽  
Pair Condensation ◽  
Copper Oxide Superconductors

We consider a parity-preserving QED 3 model with spontaneous breaking of the gauge symmetry as a framework for the evaluation of the electron–electron interaction potential underlying high-T c superconductivity. The fact that the resulting potential, -CsK0(Mr), is non-confining and "weak" (in the sense of Kato) strongly suggests the mechanism of pair-condensation. This potential, compatible with an s-wave order parameter, is then applied to the Schrödinger equation for the sake of numerical calculations, thereby enforcing the existence of bound states. The results worked out by means of our theoretical framework are checked by considering a number of phenomenological data extracted from different copper oxide superconductors. The agreement may motivate a deeper analysis of our model viewing an application to quasiplanar cuprate superconductors. The data analyzed here suggest an energy scale of 1–10 meV for the breaking of the U(1)-symmetry.

scholarly journals Electron-hole coupling in high-Tc cuprate superconductors

2005 ◽  
Vol 422 (3-4) ◽  
pp. 71-75 ◽  
Author(s):  
Alexander Brinkman ◽  
Hans Hilgenkamp
Keyword(s):  
Cuprate Superconductors ◽  
Electron Hole ◽  
High Tc

ENERGY BAND OVERLAPPING IN HIGH-Tc SUPERCONDUCTORS

1996 ◽  
Vol 10 (30) ◽  
pp. 1483-1490 ◽  
Author(s):  
M. MORENO ◽  
R. M. MÉNDEZ-MORENO ◽  
M. A. ORTIZ ◽  
S. OROZCO
Keyword(s):  
Weak Coupling ◽  
Cuprate Superconductors ◽  
Weak Coupling Limit ◽  
Band Model ◽  
Coupling Constant ◽  
High Tc Superconductors ◽  
Energy Bands ◽  
Effective Coupling ◽  
High Tc ◽  
Two Band Model

Multi-band superconductors are analyzed and the relevance of overlapping energy bands to the high-T c of these materials is studied. Within the BCS framework, a two band model with generalized Fermi surface topologies is developed. Values of the overlapped occupancy parameters for typical cuprate superconductors are obtained as a function of the ratio R and the effective coupling constant, λ, in the weak-coupling limit. The overlap scale is of the order or lower than the cutoff (Debye) energy. The typical behavior of the isotope effect is obtained. As these superconductors have transition temperatures above the phonon barrier, the results of this approach are important to the generic understanding of the high-T c superconducting mechanism.

scholarly journals EFFECTS OF c-AXIS HOPPING IN THE INTERLAYER TUNNELING MODEL OF HIGH-Tc LAYERED CUPRATES

1999 ◽  
Vol 13 (13) ◽  
pp. 1619-1632
Author(s):  
BIPLAB CHATTOPADHYAY ◽  
A. N. DAS
Keyword(s):  
Experimental Data ◽  
Transition Temperature ◽  
Cuprate Superconductors ◽  
Interlayer Coupling ◽  
Superconducting Gap ◽  
Tunneling Model ◽  
High Tc ◽  
Optimal Doping ◽  
Pair Tunneling ◽  
Layered Cuprates

We consider the interlayer pair-tunneling model for layered cuprates, including an effective single particle hopping along the c-axis. A phenomenological suppression of the c-axis hopping matrix element, by the pseudogap in cuprate superconductors, is incorporated. At optimal doping, quantities characteristic to the superconducting state, such as the transition temperature and the superconducting gap are calculated. Results from our calculations are consistent with the experimental observations with the noteworthy point that, the superconducting gap as a function of temperature shows excellent match to the experimental data. Predictions within the model, regarding T c variation with interlayer coupling, are natural outcomes which could be tested further.

Optical studies on the high Tc cuprate superconductors

1991 ◽  
Vol 43 (3) ◽  
pp. 4075
Author(s):  
Jiro Tanaka ◽  
Masaaki Shimizu ◽  
Koji Kamiya ◽  
Satoru Miyamoto ◽  
Yukio Tanaka
Keyword(s):  
Cuprate Superconductors ◽  
Optical Studies ◽  
High Tc

scholarly journals Observation of small Fermi pockets protected by clean CuO2 sheets of a high-Tc superconductor

Science ◽  
2020 ◽  
Vol 369 (6505) ◽  
pp. 833-838 ◽  
Author(s):  
So Kunisada ◽  
Shunsuke Isono ◽  
Yoshimitsu Kohama ◽  
Shiro Sakai ◽  
Cédric Bareille ◽  
...  
Keyword(s):  
Cuprate Superconductors ◽  
Parent Compound ◽  
High Critical Transition Temperature ◽  
Photoemission Spectroscopy ◽  
Hole Doping ◽  
Quantum Oscillation ◽  
Critical Transition Temperature ◽  
High Tc ◽  
Angle Resolved Photoemission Spectroscopy ◽  
Antiferromagnetic Ordering

In cuprate superconductors with high critical transition temperature (Tc), light hole-doping to the parent compound, which is an antiferromagnetic Mott insulator, has been predicted to lead to the formation of small Fermi pockets. These pockets, however, have not been observed. Here, we investigate the electronic structure of the five-layered Ba2Ca4Cu5O10(F,O)2, which has inner copper oxide (CuO2) planes with extremely low disorder, and find small Fermi pockets centered at (π/2, π/2) of the Brillouin zone by angle-resolved photoemission spectroscopy and quantum oscillation measurements. The d-wave superconducting gap opens along the pocket, revealing the coexistence between superconductivity and antiferromagnetic ordering in the same CuO2 sheet. These data further indicate that superconductivity can occur without contribution from the antinodal region around (π, 0), which is shared by other competing excitations.

scholarly journals Vibronic Mechanism of High Tc Superconductivity

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3266-3270 ◽  
Author(s):  
M. Tachiki ◽  
T. Egami ◽  
M. Machida
Keyword(s):  
Transition Temperature ◽  
Order Parameter ◽  
Cuprate Superconductors ◽  
High Temperature Superconductivity ◽  
Attractive Interaction ◽  
Low Frequencies ◽  
High Tc ◽  
Eliashberg Theory ◽  
Bond Stretching ◽  
Vibronic Effect

When phonons strongly mix with electron charge fluctuations with low frequencies, the phonon mediated attractive interaction between electrons is strongly enhanced. The occurrence of the mixing has been indicated by the neutron scattering experimental results that the dispersion of the in-plane Cu–O bond-stretching mode in the high Tc cuprate superconductors is strongly softened near the zone boundary. We propose that the phonon mediated attractive interaction strongly enhanced by the vibronic effect can form a basis for the phonon mechanism of high temperature superconductivity. With the Eliashberg theory and with the electronic structure determined by ARPES and the electronic dielectric function obtained by the softened dispersion of the in-pane Cu–O stretching mode, we calculated the transition temperature and the order parameter at the transition temperature. The order parameter is of the d(x2-y2) symmetry and the transition temperature is well in excess of 100 K.

Origins of electron–hole asymmetry in cuprate superconductors

2004 ◽  
Vol 272-276 ◽  
pp. E187-E188 ◽  
Author(s):  
A Kobayashi ◽  
A Tsuruta ◽  
T Matsuura ◽  
Y Kuroda
Keyword(s):  
Cuprate Superconductors ◽  
Electron Hole
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