Self-consistent electronic structure of a dx2-y2 and a dx2-y2+idxy vortex

We investigate quasiparticle states associated with an isolated vortex in a d-wave superconductor using a self-consistent Bogoliubov-de Gennes formalism. For a pure d(x2-y2) superconductor we find that there exist no bound states in the core; all the states are extended with continuous energy spectrum. This result is inconsistent with the existing experimental data on cuprates. We propose an explanation for this data in terms of a magnetic-field-induced d(x2-y2) + id(xy) state recently invoked in connection with the thermal conductivity measurements on Bi2Sr2CaCu2O8.