Electronic vortex structure and quasiparticle scattering in the cuprate superconductorNd2−xCexCuOy

In a superconductor with s-wave symmetry of the order parameter, in the superclean limit, the density of states $N\left(\varepsilon \right)$ of the quasiparticles in the vortex core remains zero up to the minigap ${\varepsilon }_0$ where $N\left(\varepsilon \right)$ shows a sharp upturn. Another strong increase of $N\left(\varepsilon \right)$ occurs near the superconducting energy gap Δ. These features of $N\left(\varepsilon \right)$ have important consequences for the electric-field dependence of the flux-flow resistivity. A phenomenological discussion of the resulting effects is presented and related to the two intrinsic steps in the flux-flow resistance of the cuprate superconductor ${\mathrm{Nd}}_{2-x}{\mathrm{Ce}}_x{\mathrm{CuO}}_y$ observed recently.