Impurity Effects in a Vortex Core in a Chiral p-Wave Superconductor Within the t-Matrix Approximation
We study the effects of non-magnetic impurity scattering on the Andreev bound states (ABS) in an isolated vortex in two-dimensional chiral p-wave superconductors numerically. We incorporate the impurity scattering effects into the quasiclassical Eilenberger formulation through the self-consistent t-matrix approximation. Within this scheme, we calculate the local density of states (LDOS) around two types of vortices: “parallel” (“anti-parallel”) vortex where the phase winding of the pair-potential coming from the vorticity and that coming from the chirality have the same (opposite) sign.When the scattering phase-shift δ0 of each impurity is small, we find that the impurities affect differently the spectra of quasiparticles localized around the two types of vortices in a way similar to that in the Born limit (δ0→0). For a larger δ0(≲π/2), ABS in the vortex is strongly suppressed by the impurities for both types of vortices. We find that there are some correlations between the suppression of ABS near vortex cores and the low energy density of states due to the impurity bands in the bulk.