Symmetry of the Pairing State and Transition Temperature in the P-D Model

1999 ◽  
Vol 13 (09n10) ◽  
pp. 1201-1206 ◽  
Author(s):  
R. Citro ◽  
M. Marinaro
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Experimental Results ◽  
Superconducting Transition ◽  
Cumulant Expansion ◽  
Pairing Interaction ◽  
Charge Fluctuations ◽  
D Model ◽  
Effective Pairing Interaction ◽  
Effective Pairing

The effective pairing interaction and the superconducting transition temperature Tc, mediated by both spin and charge fluctuations, are investigated on the basis of the simplest p - d model by considering a Bethe-Salpeter equation for the vertex functions within a generalized cumulant expansion. The comparison with experimental results of hole-doped cuprates is discussed.

scholarly journals Pressure dependence of the superconducting transition temperatures in La1.85Sr0.15CuO4 to 8 GPa

1987 ◽  
Vol 2 (6) ◽  
pp. 783-785 ◽  
Author(s):  
D. Erskine ◽  
E. Hess ◽  
P. Y. Yu ◽  
A. M. Stacy
Keyword(s):  
Transition Temperature ◽  
Pressure Dependence ◽  
Superconducting Transition Temperature ◽  
Diamond Anvil Cell ◽  
Experimental Results ◽  
Transition Temperatures ◽  
Superconducting Transition ◽  
Diamond Anvil ◽  
Phonon Model

Pressure dependence of the superconducting transition temperature in La1.85Sr0.15CuO4 has been measured to 8 GPa using a diamond anvil cell. The experimental results are discussed within the conventional electron-phonon model of superconductivity.

Simulation of Structural Parameters and Superconducting Transition Temperature of MgB2 under Pressure

2005 ◽  
Vol 475-479 ◽  
pp. 3319-3322
Author(s):  
Yang Shao ◽  
X. Zhang ◽  
Fu Ling Tang
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Pressure Effect ◽  
Structural Parameters ◽  
Experimental Results ◽  
Bcs Theory ◽  
Superconducting Transition ◽  
Potential Parameters

We successfully developed the potential parameters for simulation of MgB2. With these potential parameters, we calculate the lattice parameters and volume variations with pressure up to 240GPa. All these results agree well with experimental data under 40GPa and provide reasonable tendencies from 40GPa to 240GPa. By employing the McMillan expression, it is found that the lattice stiffening dominants the behavior of Tc under pressure in the scope of BCS theory. Using our calculated Grüneisen parameter G g , the simulated pressure effect on Tc accords well with experimental results. Our result shows that the Tc of MgB2 can be destroyed by high pressure.

scholarly journals SUPERCONDUCTIVITY IN NaxCoO2·yH2O DRIVEN BY THE KINETIC ENERGY

2005 ◽  
Vol 19 (01n03) ◽  
pp. 73-75 ◽  
Author(s):  
BIN LIU ◽  
YING LIANG ◽  
SHIPING FENG
Keyword(s):  
Transition Temperature ◽  
Kinetic Energy ◽  
Ground State ◽  
Qualitative Agreement ◽  
Superconducting Transition Temperature ◽  
Doping Concentration ◽  
Experimental Results ◽  
Cooper Pairs ◽  
Superconducting Transition ◽  
Mechanism Of Superconductivity

Within the charge-spin separation fermion-spin theory, the mechanism of superconductivity in Na x CoO 2·y H 2 O is studied. It is shown that dressed fermions interact occurring directly through the kinetic energy by exchanging magnetic excitations. This interaction leads to a net attractive force between dressed fermions(then the electron Cooper pairs), and their condensation reveals the superconducting ground state. The optimal superconducting transition temperature occurs in the electron doping concentration δ≈0.29, and then decreases for both underdoped and overdoped regimes, in qualitative agreement with the experimental results.

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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