scholarly journals Effect of Born and unitary impurity scattering on the Kramer–Pesch shrinkage of a vortex core in an s-wave superconductor

2013 ◽  
Vol 484 ◽  
pp. 69-73 ◽  
Author(s):  
Nobuhiko Hayashi ◽  
Yoichi Higashi ◽  
Noriyuki Nakai ◽  
Hisataka Suematsu
Keyword(s):  
Vortex Core ◽  
Impurity Scattering ◽  
S Wave

THERMAL TRANSPORT OF MgB2 SUPERCONDUCTORS: INTERPLAY BETWEEN ELECTRON AND LATTICE-IMPURITY SCATTERING

2007 ◽  
Vol 21 (26) ◽  
pp. 4517-4536 ◽  
Author(s):  
DINESH VARSHNEY ◽  
M. NAGAR ◽  
K. K. CHOUDHARY
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Phonon Scattering ◽  
Theoretical Calculations ◽  
Impurity Scattering ◽  
Metallic Phase ◽  
Scattering Mechanism ◽  
S Wave ◽  
Lattice Contribution ◽  
Relaxation Time Approximation

We use the Kubo model to calculate the lattice contribution to the thermal conductivity (κph) in MgB 2 superconductors. The theory is formulated when heat transfer is limited by the scattering of phonons from defects, grain boundaries, charge carriers, and phonons. The lattice thermal conductivity in normal state of MgB 2 superconductors dominates and is an artifact of strong phonon-impurity and -phonon scattering mechanism. Later on, the electronic contribution to the thermal conductivity (κe) is calculated within relaxation time approximation for π and σ band carriers with s wave symmetry. Such an estimate sets an upper bound on κe and is about 30% of the total heat transfer at room temperature. The validity of the Wiedemann Franz law is also examined and an enhanced Lorenz number is obtained. Both these channels for heat transfer are clubbed and κ tot develops a broad peak at about 120 K, before falling off at higher temperatures weakly. The anomalies reported are well-accounted in terms of the scattering mechanism by phonon and electron with impurities. It is shown that the behavior of the thermal conductivity is determined by competition among the several operating scattering mechanisms for the heat carriers and a balance between electron and lattice contributions. The contribution of carriers toward κ is substantial and is due to the fact that the carriers are condensed and do not carry entropy. We include comparisons with other theoretical calculations on κe and available experimental data. The numerical analysis of heat transfer in the metallic phase of MgB 2 shows similar results as those revealed from experiments.

Impurity scattering in d+s wave superconductivity

1996 ◽  
Vol 33 (4) ◽  
pp. 309-314 ◽  
Author(s):  
M. T Béal-Monod ◽  
K Maki
Keyword(s):  
Impurity Scattering ◽  
S Wave

Effect of impurity scattering on a (d+s)-wave superconductor

1995 ◽  
Vol 52 (18) ◽  
pp. 13576-13584 ◽  
Author(s):  
Heesang Kim ◽  
E. J. Nicol
Keyword(s):  
Impurity Scattering ◽  
S Wave

scholarly journals Relation of Superconducting Pairing Symmetry and Non-Magnetic Impurity Effects in Vortex States

Symmetry ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 175
Author(s):  
Yasuaki Sera ◽  
Takahiro Ueda ◽  
Hiroto Adachi ◽  
Masanori Ichioka
Keyword(s):  
Vortex Core ◽  
Magnetic Impurity ◽  
Impurity Scattering ◽  
Pairing Symmetry ◽  
Impurity Effects ◽  
Vortex States ◽  
Scattering Rate ◽  
Pairing Function ◽  
Sign Change ◽  
Anisotropic Superconductors

Non-magnetic impurity scattering effects on the vortex core states are theoretically studied to clarify the contributions from the sign-change of the pairing function in anisotropic superconductors. The vortex states are calculated by the Eilenberger theory in superconductors with p x -wave pairing symmetry, as well as the corresponding anisotropic s-wave symmetry. From the spatial structure of the pair potential and the local electronic states around a vortex, we examine the differences between anisotropic superconductors with and without sign-change of the pairing function, and estimate how twofold symmetric vortex core images change with increasing the impurity scattering rate both in the Born and the unitary limits. We found that twofold symmetric vortex core image of zero-energy local density of states changes the orientation of the twofold symmetry with increasing the scattering rate when the sign change occurs in the pairing function. Without the sign change, the vortex core shape reduces to circular one with approaching dirty cases. These results of the impurity effects are valuable for identifying the pairing symmetry by observation of the vortex core image by the STM observation.

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