Intrinsic Topological Superconductors Induced by Textured Magnetic Order: A Versatile Majorana Fermion Platform

Systems that inherently exhibit topological superconductivity are rare in nature and the highly coveted Majorana fermions are mainly pursued in engineered hybrid devices. Here we propose to harness the possible microscopic coexistence of superconductivity and magnetism as an alternative pathway to craft intrinsic topological superconductors [1]. We focus on materials with spontaneous textured magnetic order driven by Fermi surface nesting. Our work is motivated by the iron pnictides, in which such a coexistence has been shown experimentally, and a recent theoretical analysis [2] has revealed that textured magnetism is also accessible. We explore the arising topological superconducting phases in layered multiband materials with magnetic spiral, whirl or skyrmion order, coexisting with various types of spin-singlet superconductivity. The diverse magnetic phases lead to a variety of flat, unidirectional and chiral Majorana edge modes. We show that this multifaceted manifestation of Majorana fermion modes stems from the interplay of topological phases with both gapped and nodal bulk energy spectra. [1] P. Kotetes, New J. Phys. 15, 105027 (2013). [2] M. H. Christensen, B. M. Andersen and P. Kotetes, arXiv:1612.07633.