Correlation between the interlayer Josephson coupling strength and an enhanced superconducting transition temperature of multilayer cuprate superconductors

2012 ◽  
Vol 85 (5) ◽  
Author(s):  
Y. Hirata ◽  
K. M. Kojima ◽  
M. Ishikado ◽  
S. Uchida ◽  
A. Iyo ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Coupling Strength ◽  
Superconducting Transition Temperature ◽  
Cuprate Superconductors ◽  
Josephson Coupling ◽  
Superconducting Transition

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 Effect of Multiple Orders on Superconducting Transition Temperature of Hole Doped Cuprates

2017 ◽  
Vol 9 (4) ◽  
pp. 341-349
Author(s):  
I. Qabid ◽  
S. H. Naqib
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Cuprate Superconductors ◽  
Energy Gap ◽  
Density Wave ◽  
Spin Density Wave ◽  
Superconducting Transition ◽  
Electronic Density ◽  
Special Cases ◽  
Multiple Orders

Hole doped high-Tc cuprate superconductors are strongly correlated electronic systems. In these materials, various electronic orders are often found, but whether they support or compete with superconducting order is not unambiguous. Superconductivity normally manifests itself by a superconducting gap in the electronic density of states (EDOS). In cuprates, a gap appears even in the normal state called the pseudogap (PG). For certain doping range, spin density wave and charge density wave coexist with superconductivity by inducing corresponding additional gaps in the EDOS. In this study, we have tried to obtain expression for superconducting transition temperature, Tc by solving the BCS (Bardeen-Cooper-Schrieffer) energy gap equation in the presence of depleted EDOS of various origins and types. We have been successful to solve the weak-coupling BCS integral equation analytically in some special cases and also in the general case by using numerical integration. We have found that depending on conditions these non-pairing gaps/orders can enhance as well as reduce Tc.

scholarly journals INTERPLAY BETWEEN SINGLE PARTICLE COHERENCE AND KINETIC ENERGY DRIVEN SUPERCONDUCTIVITY IN DOPED CUPRATES

2004 ◽  
Vol 18 (17) ◽  
pp. 895-907 ◽  
Author(s):  
TIANXING MA ◽  
HUAIMING GUO ◽  
SHIPING FENG
Keyword(s):  
Transition Temperature ◽  
Kinetic Energy ◽  
Single Particle ◽  
Superconducting Transition Temperature ◽  
Spin Structure ◽  
Cuprate Superconductors ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Superconducting Transition ◽  
Dynamical Spin

Within the kinetic energy driven superconducting mechanism, the interplay between the single particle coherence and superconducting instability in doped cuprates is studied. The superconducting transition temperature increases with increasing doping in the underdoped regime, and reaches a maximum in the optimal doping, then decreases in the overdoped regime, however, the values of this superconducting transition temperature in the whole superconducting range are suppressed to low temperature due to the single particle coherence. Within this superconducting mechanism, we calculate the dynamical spin structure factor of cuprate superconductors, and reproduce all main features of inelastic neutron scattering experiments in the superconducting-state.

COMMON MAGNETIC ORIGIN OF THE RESONANCE PEAK AND INCOMMENSURATION IN HIGH-Tc SUPERCONDUCTORS

2000 ◽  
Vol 14 (29n31) ◽  
pp. 3334-3341 ◽  
Author(s):  
C. D. BATISTA ◽  
G. ORTIZ ◽  
A. V. BALATSKY
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Cuprate Superconductors ◽  
Resonance Peak ◽  
Low Energy ◽  
Unified Theory ◽  
Superconducting Transition ◽  
High Tc Superconductors ◽  
High Tc ◽  
Magnetic Origin

We present a unified theory for the resonance peak and low-energy incommensurate response observed in high-Tc cuprate superconductors. The origin of both features is purely magnetic and they represent universal features signaling the existence of an incommensurate spin state both below and above the superconducting transition temperature. We argue that the resonance peak is the reflection of commensurate antiferromagnetism. Our theoretical scenario gives an account of the main universal features observed in various families of superconductors and predicts those that have not been observed yet experimentally.

INTERMEDIATELY COUPLED PHONON AND CHARGE FLUCTUATION INDUCED SUPERCONDUCTIVITY IN MgB2 PROBED BY A THREE SQUARE WELL APPROACH

2008 ◽  
Vol 22 (14) ◽  
pp. 2285-2308 ◽  
Author(s):  
DINESH VARSHNEY ◽  
M. NAGAR ◽  
R. K. SINGH
Keyword(s):  
Transition Temperature ◽  
Isotope Effect ◽  
Coupling Strength ◽  
Superconducting Transition Temperature ◽  
Electron Interaction ◽  
Charge Fluctuation ◽  
Superconducting Transition ◽  
Effective Electron ◽  
Screening Parameter ◽  
Square Well

A three square well model is developed, which allows one to easily calculate the correlation between the coupling strength parameters and superconducting transition temperature (T c ), pressure and volume derivative of T c and isotope effect exponent for MgB 2. Upon considering the three interactions, namely, electron-phonon, electron-plasmon and Coulomb, the analytical solutions for the energy gap equation allow us to understand the relative interplay of these interactions. The values of the coupling strength and of the Coulomb interaction parameter indicate that the superconductor is in the intermediate coupling regime. The superconducting transition temperature of MgB 2 for the 2D band is estimated as 41 K for [Formula: see text] and μσ*≈0.28. We present correlation curves of T c with various coupling strengths as electron-phonon [Formula: see text], electron-plasmon [Formula: see text] and the Coulomb screening parameter (μσ*). The present approach also explains the reported boron isotope effect and the pressure derivative of T c in the test material. We suggest from these results that both the plasmons and phonons within the framework of a three square well scheme consistently explain the effective electron-electron interaction leading to superconductivity in MgB 2. The implications of the effective interactive potential with both σ and π carriers and its analysis are discussed.

scholarly journals Enhancing Superconductivity of the Nonmagnetic Quasiskutterudites by Atomic Disorder

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5830
Author(s):  
Andrzej Ślebarski ◽  
Maciej M. Maśka
Keyword(s):  
High Temperature ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
High Temperature Superconductors ◽  
Superconducting Phase ◽  
Length Scale ◽  
Superconducting Transition ◽  
Atomic Disorder ◽  
Strong Inhomogeneity ◽  
Related Compounds

We investigated the effect of enhancement of superconducting transition temperature Tc by nonmagnetic atom disorder in the series of filled skutterudite-related compounds (La3M4Sn13, Ca3Rh4Sn13, Y5Rh6Sn18, Lu5Rh6Sn18; M= Co, Ru, Rh), where the atomic disorder is generated by various defects or doping. We have shown that the disorder on the coherence length scale ξ in these nonmagnetic quasiskutterudite superconductors additionally generates a non-homogeneous, high-temperature superconducting phase with Tc⋆>Tc (dilute disorder scenario), while the strong fluctuations of stoichiometry due to increasing doping can rapidly increase the superconducting transition temperature of the sample even to the value of Tc⋆∼2Tc (dense disorder leading to strong inhomogeneity). This phenomenon seems to be characteristic of high-temperature superconductors and superconducting heavy fermions, and recently have received renewed attention. We experimentally documented the stronger lattice stiffening of the inhomogeneous superconducting phase Tc⋆ in respect to the bulk Tc one and proposed a model that explains the Tc⋆>Tc behavior in the series of nonmagnetic skutterudite-related compounds.

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