Magnetic atom chain platform for Majorana fermions

Magnetic atom chains on the surface of a conventional superconductor provide a novel approach to realize a topological superconductor, which host Majorana fermions at the edge of 1D chains. Here we report a self-assembled magnetic atomic chain structure on a two dimensional (2D) superconductor, which provides a platform for future research on the Majorana fermions. We grow the helimagnet Mn1/4TaS2 single crystal, which is Mn atoms intercalated into the vdW gaps of 2H-TaS2 to form an ordered lattice. Using scanning tunneling microscope, we confirm the 2x2 Mn superstructure, and magnetic Mn atom chains on the surface after in situ cleaving. This self-assembled behavior is temperature dependent, that Mn atoms show 2x2 periodicity when cleaved at low temperature, while form atomic chains when cleaved at room temperature and annealed at higher temperature. With careful selection of annealing temperature and time, isolated chains can be obtained and are promisng for the formation of a topological phase and Majorana fermions.