Effects of nonmagnetic scatterers on the local density of states around a vortex in s-wave superconductors

We study the effect of nonmagnetic impurities on the local density of states (LDOS) in the mixed state of s-wave superconductors. The quasiclassical equations of superconductivity in the vortex state are solved self-consistently to show how the LDOS evolves with impurity concentration. The spatially averaged zero-energy LDOS is a linear function of magnetic induction in low fields, N(E=0)=α(τ)B/H_c2, for all impurity concentrations. The coefficient α depends weakly on the electron mean-free path. We evaluate numerically the differential conductance and spatial profiles of zero-energy LDOS, which can help in extracting the mean-free path from the measured LDOS.