Engineering nodal topological phases in Ising superconductors by magnetic superstructures

Abstract: Recently it was discovered that superconductivity in transition metal dichalcogenides (TMDs) is strongly affected by an out-of-plane spin-orbit coupling (SOC). In addition, new techniques of fabricating 2d ferromagnets on van der Waals materials are rapidly emerging. Combining these breakthroughs, we propose a realization of nodal topological superconductivity in TMDs by fabricating nanostructured ferromagnets with an in-plane magnetization on the top surface. The proposed procedure does not require application of external magnetic fields and applies to monolayer and multilayer (bulk) systems. The signatures of the topological phase include Majorana flat bands that can be directly observed by Scanning Tunneling Microscopy (STM) techniques. We concentrate on NbSe$_2$ and argue that the proposed structures demonstrating the nodal topological phase can be realized withing existing technology.