Pressure coefficient of the superconducting transition temperature within the van Hove scenario

1995 ◽  
Vol 52 (17) ◽  
pp. 12545-12547 ◽  
Author(s):  
Sujit Sarkar ◽  
S. Basu ◽  
A. N. Das
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Pressure Coefficient ◽  
Superconducting Transition ◽  
Van Hove Scenario

scholarly journals Isotopeneffekt und Druckkoeffizient der Übergangstemperatur zur Supraleitung in der Eliashberg-Theorie / Isotope Effect and Pressure Coefficient of the Superconducting Transition Temperature within the Eliashberg-Theory

1975 ◽  
Vol 30 (2) ◽  
pp. 250-255
Author(s):  
W. Kessel
Keyword(s):  
Transition Temperature ◽  
Isotope Effect ◽  
Superconducting Transition Temperature ◽  
Pressure Coefficient ◽  
Volume Control ◽  
Superconducting Transition ◽  
Eliashberg Equations ◽  
Eliashberg Theory ◽  
Fundamental Parameters ◽  
Experimental Values

Abstract Isotope Effect and Pressure Coefficient of the Superconducting Transition Temperature within the Eliashberg-Theory Starting from the observation that both the mass of the ions and their volume control the phonon frequencies by stretching the phonon spectrum, the change of the Eliashberg-equations of the theory of superconductivity regarding these stretchings is considered. General expressions for the isotopic exponent and the pressure coefficient of the transition temperature are derived in which only derivatives of the transition temperature with respect to the fundamental parameters of the theory are involved. A comparison with experimental values shows that lead is not the metal with the highest transition temperature possible under the simple metals.

PRESSURE COEFFICIENT OF THE SUPERCONDUCTING TRANSITION TEMPERATURE IN THE STRONG COUPLING LIMIT

1996 ◽  
Vol 10 (18) ◽  
pp. 839-843 ◽  
Author(s):  
S. BASU ◽  
SUJIT SARKAR ◽  
S. SIL
Keyword(s):  
Transition Temperature ◽  
Superconducting Transition Temperature ◽  
Pressure Coefficient ◽  
Coulomb Repulsion ◽  
Dimensional System ◽  
Superconducting Transition ◽  
Eliashberg Equation ◽  
Underdoped Region ◽  
Two Dimensional System ◽  
Einstein Approximation

Pressure coefficient (β) of the superconducting transition temperature (T c ) for a two dimensional system is studied in presence of Coulomb interaction, using Eliashberg equation with the Einstein approximation for the phonon system, within the van Hove scenario. β is found to be high in the low-T c region and low in the high-T c region. β is positive in the underdoped region and becomes negative in the overdoped region. For a given value of Fermi energy, β increases in the underdoped region and decreases in the overdoped region with the increase of Coulomb repulsion.

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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