Topological electronic structure near linear defects in iron-based superconductors*

Recent experiments [1, 2] have suggested that topological superconducting states (TSS) in Fe-based superconductors may support Majorana zero modes  near linear defects. Some studies [3] suggest that the defect constitutes an effective ferromagnetic chain, which is known to support Majorana end chain excitations when coupled to a superconductor in the presence of spin orbit coupling, whereas others suggest antiferromagnetic correlations may accomplish a similar goal. Ways to obtain TSS from singlet unconventional superconductors have also been proposed [4] via inversion symmetry breaking. Here we study realistic models of iron-based superconductors with linear defects within a spin-generalized and spin-rotationally invariant BdG framework, and discuss the defect-induced novel magnetic states and superconducting gap structures.

Ref: 

1. Nature Physics 16, 536-540 (2020) 

2. Science 346, 602 (2014) 

3. Phys. Rev. B 90, 235433 (2014) 

4. Phys. Rev. X 11, 011041 (2021)