Europhys. Lett., 63 (1) , pp. 111-117 (2003)
Quasiparticle delocalization induced by novel quantum interference in disordered d-wave superconductorsY. H. Yang1, 2, 3, D. Y. Xing1, M. Liu2 and Y. G. Wang2
1 National Laboratory of Solid State Microstructures Nanjing University - Nanjing 210008, PRC
2 Department of Physics, Southeast University - Nanjing 210096, PRC
3 Department of Physics, Tunghai University - Taichung 181, Taiwan
(Received 8 October 2002; accepted in final form 25 April 2003)
The diagrammatic approach is applied to study quasiparticle transport properties in two-dimensional d-wave superconductors with dilute, substitutional nonmagnetic impurities both in Born and in unitary limits. It is found that a novel quantum interference process gives rise to a weak-antilocalization correction to the spin conductivity, indicating the existence of extended low-energy quasiparticle states. When coming close to unitarity and nesting, this correction is suppressed and eventually vanishes due to the global particle-hole symmetry.
74.25.Fy - Transport properties (electric and thermal conductivity, thermoelectric effects, etc.).
73.20.Fz - Weak or Anderson localization.
74.20.-z - Theories and models of superconducting state.
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