Ginzburg–Landau Equations for a d-Wave Superconductor with Paramagnetic Impurities

1998 ◽  
Vol 12 (10) ◽  
pp. 1069-1095 ◽  
Author(s):  
Wonkee Kim ◽  
C. S. Ting

Ginzburg–Landau (GL) equations for a d-wave superconductor with a repulsive s-wave interaction between electrons in the presence of paramagnetic impurities are microscopically derived based on the Born approximation. The diagrammatic relationships for the impurity-averaged product of Green's functions are algebraically established. The effect of paramagnetic impurities on the transition temperature and the London penetration depth are discussed. GL equations for a superconductor with both s-wave and d-wave pairing interactions are also examined. We show that the transition temperature for a superconductor with an s-wave symmetry is suppressed twice as rapidly as that with a d-wave symmetry in the dilute impurity limit if the strength of the spin-non-flip scattering is much weaker than the spin-flip interaction.

1996 ◽  
Vol 10 (12) ◽  
pp. 537-544 ◽  
Author(s):  
SERGEI V. POKROVSKY

It is shown by direct calculations that in a superconductor with a slightly violated d-wave symmetry of the order parameter (OP) the impurity driven phase transition from the gapless superconductivity to a state with a finite gap takes place at zero temperature. The corresponding scattering rate is close to the value at which the superconductivity vanishes in the d-superconductor. The behavior of the transition temperature, the OP and the density of states (DOS) is analyzed. The model is plausibly relevant to the BSCCO 2:2:1:2.


2002 ◽  
Vol 16 (20n22) ◽  
pp. 3175-3175
Author(s):  
A. BISWAS ◽  
P. FOURNIER ◽  
V. N. SMOLYANINOVA ◽  
H. BALCI ◽  
J. S. HIGGINS ◽  
...  

The properties of electron(n)-doped cuprate superconductors show significant deviations from those of their hold(p)-doped counterparts. Experiments prior to 2000 suggested an s-wave pairing symmetry as opposed to d-wave pairing symmetry in hole-doped cuprates. Recent experiments have suggested that n-doped cuprates have a d-wave pairing symmetry. However tunneling spectroscopy of these materials have not revealed a zero bias conductance peak (ZBCP), which is a classic signature of d-wave symmetry. We present the first tunneling spectroscopy data on n-doped Pr 2-x Ce x CuO 4 (PCCO) using point contact junctions which show a systematic evolution of the ZBCP. This method of junction fabrication is important as it allows the barrier strength between the normal and the superconducting electrodes to be varied. We show that this is essential to observing the ZBCP. The n-doped cuprates have a low Tc (~25 K ) and Hc2 (~10 T ). The low Hc2 enables us to obtain the normal state in PCCO at low temperatures. We have used this to probe the density of states in the normal state of PCCO. We observe an anomalous gap even in the normal state.1 This normal state gap (NSG) becomes smaller on the over-doped side. We discuss the behavior of this NSG in the context of the pseudogap which has been observed in hole-doped cuprates.


1999 ◽  
Vol 13 (09n10) ◽  
pp. 1301-1306
Author(s):  
G. A. Ummarino ◽  
R. S. Gonnelli ◽  
C. Bravi ◽  
Masumi Inoue

A new possible indirect way of testing pair symmetry in high-Tc superconductors has been set up. The degree of intrinsic gap depression at Superconductor-Insulator [S-I] interfaces required to match Ic(T)Rn(T) data in HTS Josephson junctions depends on the pair symmetry of the material itself, so that an higher fraction of d-wave symmetry for the order parameter requires less gap depression, while an higher fraction of s-wave corresponds to a larger degree of gap depression. In order to obtain a general reference value for the intrinsic amount of gap depression at S-I interfaces the de Gennes condition has been used, and resulting reduced Ic(T)Rn(T) data have been calculated in the framework of a mixed (s+id)-wave pair symmetry for the depressed order parameter ranging from pure s to pure d-wave. This model has been tentatively applied to two junctions' made of very different HTSs: YBCO and BKBO, yielding a result of almost pure d-wave for YBCO and of pure s-wave for BKBO.


1966 ◽  
Vol 21 (11) ◽  
pp. 1842-1849 ◽  
Author(s):  
Gerhart Lüders

The method of correlation function is extended to the case of paramagnetic impurities. The BOLTZMANN equation is obtained and subsequently applied to a derivation of the concentration dependence of the transition temperature, of the linearized GINZBURG—LANDAU equation, and of the diffusion approximation.


Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1341 ◽  
Author(s):  
Giovanni Alberto Ummarino ◽  
Antonio Gallerati

We study the behaviour of a superconductor in a weak static gravitational field for temperatures slightly greater than its transition temperature (fluctuation regime). Making use of the time-dependent Ginzburg–Landau equations, we find a possible short time alteration of the static gravitational field in the vicinity of the superconductor, providing also a qualitative behaviour in the weak field condition. Finally, we compare the behaviour of various superconducting materials, investigating which parameters could enhance the gravitational field alteration.


2004 ◽  
Vol 412-414 ◽  
pp. 352-357 ◽  
Author(s):  
Masaru Kato ◽  
Masayuki Ako ◽  
Masahiko Machida ◽  
Tomio Koyama ◽  
Takekazu Ishida
Keyword(s):  
S Wave ◽  

2020 ◽  
Vol 5 (3) ◽  
pp. 50
Author(s):  
Rustem Khasanov ◽  
Alexander Shengelaya ◽  
Roland Brütsch ◽  
Hugo Keller

The temperature dependencies of the in-plane (λab) and out-of-plane (λc) components of the magnetic field penetration depth were investigated near the surface and in the bulk of the electron-doped superconductor Sr0.9La0.1CuO2 by means of magnetization measurements. The measured λab(T) and λc(T) were analyzed in terms of a two-gap model with mixed s+d-wave symmetry of the order parameter. λab(T) is well described by an almost pure anisotropic d-wave symmetry component (≃96%), mainly reflecting the surface properties of the sample. In contrast, λc(T) exhibits a mixed s+d-wave order parameter with a substantial s-wave component of more than 50%. The comparison of λab−2(T) measured near the surface with that determined in the bulk by means of the muon-spin rotation/relaxation technique demonstrates that the suppression of the s-wave component of the order parameter near the surface is associated with a reduction of the superfluid density by more than a factor of two.


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