Phase-Sensitive Impurity Effects in Vortex Core of Moderately Clean Chiral Superconductors

Abstract

We study impurity effects in vortex core of two-dimensional moderately clean su perconductors within the quasiclassical theory. The impurity scattering rate $\G amma(E)$ of the Andreev bound states in vortex core with +1 vorticity of p-wav e superconductors with ${\mib d}=\hat{\mib z}(p_x+\iu p_y)$ is suppre ssed, compared to the normal state scattering rate $Γ_{\rm n}$ in the energ y region $Γ_{\rm n}^3/E_δ^2\ll E\ll E_δ\equiv |δ_0|Δ_ınfty$ with scattering phase shift $δ_0$ $(|δ_0|\ll 1)$ and the pair-po tential in bulk $Δ_\infty$. Further we find that $Γ(E)/Γ_{\rm n}$ for p-wave superconductors with ${\mib d}=\hat{\mib z}(p_x-\iu p_y)$ is at most ${\cal O}(E/Δ_ınfty)$. These results are in marked contrast to the even-parity case (s,d-wave), where $Γ(E)/Γ_{\rm n}$ is known to be proportional to $\ln(Δ_ınfty/E)$ . Parity- and chirality-dependences of impurity effects are attributed to the Andr eev reflections involved in the impurity-induced scattering between bound states . Implications for the flux flow conductivity is also discussed. Novel enhanceme nt of flux flow conductivity is expected to occur at $T\ll E_δ$ for ${\mib d}=\hat{\mib z}(p_x+\iu p_y)$ and at $T\ll Δ_\infty$ for ${\mib d}=\hat{\mib z}(p_x-\iu p_y)$.