Impurity states in antiferromagnetic Iron Arsenides

TL;DR

This paper theoretically investigates impurity states in the antiferromagnetic spin-density wave phase of iron arsenides, revealing bound states and their spin-dependent degeneracies using different impurity models.

Contribution

It introduces a comparative theoretical analysis of impurity states with intraband and interband scattering in iron arsenide antiferromagnets.

Findings

Impurity bound states appear in the energy gap in both models.

The bound state is spin-degenerate with intraband scattering.

The bound state is spin-polarized with combined scattering.

Abstract

We explore theoretically impurity states in the antiferromagnetic spin-density wave state of the iron arsenide. Two types of impurity models are employed: one has only the intraband scattering while the other has both the intraband and interband scattering with the equal strength. Interestingly, the impurity bound state is revealed around the impurity site in the energy gap for both models. However, the impurity state is doubly degenerate with respect to spin for the first case; while the single impurity state is observed in either the spin-up or spin-down channel for the second one. The impurity-induced variations of the local density of states are also examined.