Impurity-induced tunneling-mediated superconducting gap in bilayer cuprate superconductors

2019 ◽  
Vol 33 (02) ◽  
pp. 1950013 ◽  
Author(s):  
B. Pradhan
Keyword(s):  
Order Parameter ◽  
Cuprate Superconductors ◽  
Particle Energy ◽  
Superconducting Gap ◽  
Electronic Specific Heat ◽  
Energy Bands ◽  
Quasi Particle ◽  
Model Hamiltonian ◽  
Double Time ◽  
Parameter Density

We have proposed a model Hamiltonian describing the interlayer tunneling in d-wave bilayer cuprate superconductors. The Hamiltonian is solved for the quasi-particle energy bands and the superconducting (SC) order parameter by using Zubarev’s technique of double time Green’s functions. The effects of interlayer tunneling and the strength of non-magnetic potential are studied for SC order parameter, density of states (DOS), electronic specific heat and quasi-particle energy bands, and the results are compared with others.

EFFECT OF EXTERNAL MAGNETIC FIELD ON AFM ORDER PARAMETER AND NEEL TEMPERATURE IN ELECTRON DOPED CUPRATE SUPERCONDUCTORS

2009 ◽  
Vol 23 (26) ◽  
pp. 3125-3135 ◽  
Author(s):  
B. N. PANDA ◽  
B. K. SAHOO
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Order Parameter ◽  
Cuprate Superconductors ◽  
Antiferromagnetic Order ◽  
Neel Temperature ◽  
Néel Temperature ◽  
Double Time ◽  
Experimental Findings ◽  
Good Agreement

A theoretical model is presented to study the effect of an external magnetic field on antiferromagnetic (AFM) order parameter and Neel temperature in electron doped high TC cuprates in normal state. The expression for the antiferromagnetic order parameter is derived by using double time electron Green function of Zubarev type and studied numerically. It is found that the magnetic field up to a certain parametric value considerably enhances the Neel temperature. Above this value, the Neel temperature decreases on increasing the field. The trend of field dependence of the AFM order parameter at 30 K is quite similar to that of Neel temperature. This parametric study of external magnetic field is in good agreement with experimental findings.

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.

A POSSIBLE FIRST PRINCIPLE ARGUMENTS ON THE SYMMETRY OF SUPERCONDUTING GAP PARAMETER

1999 ◽  
Vol 13 (29n31) ◽  
pp. 3440-3442 ◽  
Author(s):  
CHANGDE GONG
Keyword(s):  
Experimental Data ◽  
Theoretical Prediction ◽  
Cuprate Superconductors ◽  
Superconducting Gap ◽  
First Principle ◽  
General Physical ◽  
Gap Parameter

The symmetry of superconducting gap parameter in high-Tc cuprate superconductors has been studied based on general physical considerations. The disagreement between theoretical prediction and experimental data is discussed.

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.

Unrelated BCS-like pairing pseudogap and critical superconducting transition temperature in various cuprate compounds

2018 ◽  
Vol 32 (18) ◽  
pp. 1850195
Author(s):  
S. Dzhumanov ◽  
E. X. Karimboev ◽  
Sh. S. Djumanov
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Order Parameter ◽  
Cuprate Superconductors ◽  
Energy Gap ◽  
Characteristic Temperature ◽  
Superconducting Order Parameter ◽  
Superconducting Transition ◽  
Gap Formation ◽  
Arpes Data

The smooth evolution of the energy gap observed in the tunneling and angle-resolved photoemission spectra (ARPES) of high-[Formula: see text] cuprates with lowering the temperature from a pseudogap state above the critical temperature [Formula: see text] to a superconducting state below [Formula: see text], has been poorly interpreted as the evidence that the pseudogap must have the same origin as the superconducting order parameter, and therefore, must be related to [Formula: see text]. We argue that such an explanation of the tunneling gap and ARPES data is misleading. We show that the BCS-like energy gap (or pseudogap) opening in the electronic excitation spectrum of underdoped-to-overdoped cuprates at a characteristic temperature [Formula: see text] and the true superconducting order parameter appearing only at [Formula: see text] are unrelated. The superconducting phenomenon in unconventional cuprate superconductors is fundamentally different from the BCS-like pairing of fermionic quasiparticles, and the superconducting transition temperature [Formula: see text] is not determined by the BCS-like gap formation. The unusual superconducting order parameter in these high-[Formula: see text] materials appears at [Formula: see text] and coexists with the BCS-like gap (or pseudogap) below [Formula: see text].

scholarly journals Intertwined Vestigial Order in Quantum Materials: Nematicity and Beyond

2019 ◽  
Vol 10 (1) ◽  
pp. 133-154 ◽  
Author(s):  
Rafael M. Fernandes ◽  
Peter P. Orth ◽  
Jörg Schmalian
Keyword(s):  
Order Parameter ◽  
Cuprate Superconductors ◽  
Primary Phase ◽  
Nematic Order ◽  
Unconventional Superconductors ◽  
Underlying Principle ◽  
Microscopic Models ◽  
Quantum Materials ◽  
Component Order

A hallmark of the phase diagrams of quantum materials is the existence of multiple electronic ordered states, which, in many cases, are not independent competing phases, but instead display a complex intertwinement. In this review, we focus on a particular realization of intertwined orders: a primary phase characterized by a multi-component order parameter and a fluctuation-driven vestigial phase characterized by a composite order parameter. This concept has been widely employed to elucidate nematicity in iron-based and cuprate superconductors. Here we present a group-theoretical framework that extends this notion to a variety of phases, providing a classification of vestigial orders of unconventional superconductors and density waves. Electronic states with scalar and vector chiral order, spin-nematic order, Ising-nematic order, time-reversal symmetry-breaking order, and algebraic vestigial order emerge from one underlying principle. The formalism provides a framework to understand the complexity of quantum materials based on symmetry, largely without resorting to microscopic models.

STM/STS and electronic specific heat of high-Tc cuprates symmetry of the order parameter

1996 ◽  
Vol 263 (1-4) ◽  
pp. 225-231 ◽  
Author(s):  
M. Ido ◽  
M. Oda ◽  
N. Momono ◽  
C. Manabe ◽  
T. Nakano
Keyword(s):  
Specific Heat ◽  
Order Parameter ◽  
Electronic Specific Heat ◽  
High Tc ◽  
High Tc Cuprates
Sign in / Sign up

Export Citation Format

Share Document