Europhys. Lett.
Volume 63, Number 1, July 2003
Page(s) 111 - 117
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 01 June 2003
DOI: 10.1209/epl/i2003-00485-9
Europhys. Lett., 63 (1) , pp. 111-117 (2003)

Quasiparticle delocalization induced by novel quantum interference in disordered d-wave superconductors

Y. 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.

© EDP Sciences 2003