scholarly journals Different length scales for order parameters in two-gap superconductors: Extended Ginzburg-Landau theory

2011 ◽  
Vol 84 (6) ◽  
Author(s):  
L. Komendová ◽  
M. V. Milošević ◽  
A. A. Shanenko ◽  
F. M. Peeters
Keyword(s):  
Landau Theory ◽  
Order Parameters ◽  
Ginzburg Landau ◽  
Length Scales

scholarly journals Specific heat jump of two-band superconductor KFe2As2 using Ginzburg-Landau theory

2014 ◽  
Vol 32 (3) ◽  
pp. 465-469 ◽  
Author(s):  
I. Askerzade
Keyword(s):  
Specific Heat ◽  
Order Parameter ◽  
Landau Theory ◽  
Energy Functional ◽  
Order Parameters ◽  
Ginzburg Landau ◽  
Specific Heat Jump ◽  
Nonlinear Temperature Dependence ◽  
Nonlinear Temperature ◽  
Good Agreement

AbstractIn this study specific heat jump using two-gap Ginzburg-Landau (GL) theory has been calculated. In contrast to the previous approaches, we have taken into account intergradient order parameters interaction in the GL free energy functional. The thermodynamic magnetic field revealed nonlinear temperature dependence due to interband interaction between order parameters and their gradients. The calculations showed that the specific heat jump in two-order parameter superconductors was smaller than that of single-order parameter superconductors. It has been shown that such a model is in good agreement with experimental data for KFe2As2 superconductors.

GENERALISED GINZBURG-LANDAU THEORY FOR HIGH Tc SUPERCONDUCTORS

1988 ◽  
Vol 02 (06) ◽  
pp. 1513-1536 ◽  
Author(s):  
M. P. DAS ◽  
HONG-XING HE ◽  
T. C. CHOY
Keyword(s):  
High Temperature Superconductivity ◽  
Landau Theory ◽  
Strong Support ◽  
Microscopic Theory ◽  
Order Parameters ◽  
Abrikosov Vortex ◽  
Ginzburg Landau ◽  
Structural Distortions ◽  
Coupling Parameters ◽  
Local Gauge Invariance

In the absence of a consensus for the correct microscopic theory for high temperature superconductivity we have devoted earlier efforts to obtain a generalised Ginzburg-Landau (GL) phenomenological model. Originally the main motivation was to examine how GL theory could be generalised. Neglecting secondary order parameters like structural distortions, oxygen vacancies etc. whose effects are integrated out and phenomenologically treated in the GL coupling parameters, we concentrate on the superconducting order parameters. The resulting theory which emerged indicates severe constraints in the parameter space of models due to local gauge invariance. Now recent experiments by several groups on specific heat and conductivity fluctuations lend strong support to this theory. Additional predictions on gap parameters and tunnelling properties are exotic and could be verified. The magnetic and Abrikosov vortex states appear to be complicated and require further study.

scholarly journals Possible Alterations of Local Gravitational Field Inside a Superconductor

Entropy ◽  
2021 ◽  
Vol 23 (2) ◽  
pp. 193 ◽  
Author(s):  
Giovanni Alberto Ummarino ◽  
Antonio Gallerati
Keyword(s):  
Gravitational Field ◽  
Landau Theory ◽  
Time Dependent ◽  
Qualitative Comparison ◽  
Ginzburg Landau ◽  
High Tc ◽  
Gravitational Fields ◽  
Favorable Conditions

We calculate the possible interaction between a superconductor and the static Earth’s gravitational fields, making use of the gravito-Maxwell formalism combined with the time-dependent Ginzburg–Landau theory. We try to estimate which are the most favorable conditions to enhance the effect, optimizing the superconductor parameters characterizing the chosen sample. We also give a qualitative comparison of the behavior of high–Tc and classical low–Tc superconductors with respect to the gravity/superfluid interplay.

Ginzburg–Landau theory of the Abrikosov vortex state near the upper critical field

1982 ◽  
Vol 60 (3) ◽  
pp. 299-303 ◽  
Author(s):  
A. E. Jacobs
Keyword(s):  
Critical Field ◽  
Landau Theory ◽  
Upper Critical Field ◽  
Vortex State ◽  
Quantization Condition ◽  
Abrikosov Vortex ◽  
Ginzburg Landau ◽  
Type Ii Superconductors ◽  
Flux Quantization ◽  
The Magnetic Field

A method which preserves the flux-quantization condition in all orders of perturbation theory is applied to the Ginzburg–Landau theory of type-II superconductors near the upper critical field. Expansions are obtained for the order parameter, the magnetic field, and the free energy; previous results are verified and extended to one higher order in Hc2 – Ha.

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