scholarly journals Suppression of the s-Wave Order Parameter Near the Surface of the Infinite-Layer Electron-Doped Cuprate Superconductor Sr0.9La0.1CuO2

2020 ◽  
Vol 5 (3) ◽  
pp. 50
Author(s):  
Rustem Khasanov ◽  
Alexander Shengelaya ◽  
Roland Brütsch ◽  
Hugo Keller
Keyword(s):  
Order Parameter ◽  
Muon Spin ◽  
Muon Spin Rotation ◽  
Wave Component ◽  
S Wave ◽  
Infinite Layer ◽  
Wave Symmetry ◽  
Out Of Plane ◽  
The Magnetic Field ◽  
D Wave

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.

Pair Symmetry and Degree of Gap Depression at S-I Interfaces in HTS Josephson Junctions

1999 ◽  
Vol 13 (09n10) ◽  
pp. 1301-1306
Author(s):  
G. A. Ummarino ◽  
R. S. Gonnelli ◽  
C. Bravi ◽  
Masumi Inoue
Keyword(s):  
Josephson Junctions ◽  
Order Parameter ◽  
Reference Value ◽  
High Tc Superconductors ◽  
S Wave ◽  
General Reference ◽  
High Tc ◽  
Wave Symmetry ◽  
Set Up ◽  
D Wave

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.

Verification of Nodeless Superconducting Pairing in Single-Crystal YBa2Cu3O7

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3582-3593 ◽  
Author(s):  
Dale R. Harshman ◽  
W. J. Kossler ◽  
X. Wan ◽  
A. T. Fiory ◽  
A. J. Greer ◽  
...  
Keyword(s):  
Single Crystal ◽  
Muon Spin ◽  
Vortex Pinning ◽  
Muon Spin Rotation ◽  
Superconducting Transition ◽  
S Wave ◽  
Flux Lattice ◽  
Field Dependent ◽  
Superconducting Pairing ◽  
D Wave

The temperature and field dependence of the penetration depth was determined from muon spin rotation (μ+ SR ) measurements on a single crystal of YBa 2 Cu 3 O 7 having a superconducting transition at Tc ≈ 91.3 K . Data were acquired at applied magnetic fields of 0.05, 1.0, 3.0, and 6.0 Tesla, yielding results inconsistent with any pairing state requiring nodes, including d-wave pairing. These data are, however, completely consistent with s-wave (or extended s-wave) superconductivity, with clear evidence of field-dependent, temperature-activated vortex pinning. Our results confirm the s-wave character originally observed in 1989, and show that the features of μ+ SR (and microwave) data used by other authors as evidence for d-wave superconductivity are instead due to temperature- and field-dependent vortex pinning/reordering, resulting in significant distortion of the flux lattice.

DENSITY OF STATES AND ORDER PARAMETER IN DIRTY SUPERCONDUCTORS WITH A WEAKLY BROKEN d-WAVE SYMMETRY

1996 ◽  
Vol 10 (12) ◽  
pp. 537-544 ◽  
Author(s):  
SERGEI V. POKROVSKY
Keyword(s):  
Phase Transition ◽  
Transition Temperature ◽  
Density Of States ◽  
Order Parameter ◽  
Zero Temperature ◽  
Scattering Rate ◽  
Wave Symmetry ◽  
Direct Calculations ◽  
D Wave ◽  
Gapless Superconductivity

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.

scholarly journals Electronic Contribution to the Thermal Diffusivity: DyBa2Cu3O7-y and Y0.9Ca0.1Ba2Cu3O7-z

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3087-3090 ◽  
Author(s):  
S. Dorbolo ◽  
H. Bougrine ◽  
M. Ausloos
Keyword(s):  
Thermal Conductivity ◽  
Thermal Diffusivity ◽  
Band Structure ◽  
Order Parameter ◽  
Saddle Points ◽  
Three Dimensional ◽  
Electronic Contribution ◽  
Wave Symmetry ◽  
D Wave ◽  
Good Agreement

The electronic contribution to the specific heat and the thermal conductivity of high-T c superconductors is calculated with a three-dimensional band structure including saddle points and a Lawrence–Doniach coupling between the CuO2 planes. The electronic thermal diffusivity is deduced for s- and d-wave symmetry of the order parameter. Data on DyBa2Cu3O 7-y and Y0.9Ca0.1Ba2Cu3O 7-z and theory are in good agreement on the change of the slope near T c .

On the Origin of Zero-Bias Conductance Peak in High-Tc Superconductors

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3027-3030
Author(s):  
Alexander B. Nazarenko ◽  
Ernst A. Pashitskii ◽  
Alexander E. Pashitskii
Keyword(s):  
Elastic Scattering ◽  
Order Parameter ◽  
Magnetic Impurities ◽  
High Tc Superconductors ◽  
Zero Bias ◽  
High Tc ◽  
Conductance Peak ◽  
Wave Symmetry ◽  
Zero Bias Conductance ◽  
D Wave

We show that the zero-bias conductance peak observed in tunnel and point junctions of cuprates can be a consequence of "unitary" elastic scattering of the carriers by non-magnetic impurities in the vicinity of the junction interface and d-wave symmetry of the order parameter.

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
Keyword(s):  
Transition Temperature ◽  
Born Approximation ◽  
Wave Interaction ◽  
London Penetration Depth ◽  
S Wave ◽  
Ginzburg Landau ◽  
Paramagnetic Impurities ◽  
Wave Symmetry ◽  
Ginzburg Landau Equations ◽  
D Wave

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.

TUNNELING SPECTROSCOPY OF THE ELECTRON-DOPED CUPRATE SUPERCONDUCTOR Pr2-xCexCuO4

2002 ◽  
Vol 16 (20n22) ◽  
pp. 3175-3175
Author(s):  
A. BISWAS ◽  
P. FOURNIER ◽  
V. N. SMOLYANINOVA ◽  
H. BALCI ◽  
J. S. HIGGINS ◽  
...  
Keyword(s):  
Normal State ◽  
Cuprate Superconductors ◽  
Point Contact ◽  
Tunneling Spectroscopy ◽  
Pairing Symmetry ◽  
S Wave ◽  
Zero Bias ◽  
Wave Pairing ◽  
Wave Symmetry ◽  
D Wave

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.

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