Observation of intrinsic topological superconductivity in transition metal dichalcogenide

Topological superconductors may harbor non-Abelian excitation on its boundaries such as Majorana zero mode – an essential ingredient for quantum information processing. Although, Majorana edge mode has been observed in several hybrid heterostructures and epitaxially grown materials, it is yet to be demonstrated in a layered stoichiometric material. This is essential to eliminate disorder induced artifacts and to design robust devices for quantum computing. Here, we used scanning tunneling microscopy to visualize the boundary states of intrinsic topological superconductivity in a transition metal dichalcogenide (TMD). We observed a zero-bias peak at the vortex core as well as an exponentially localized in-gap edge mode on the step edges along arbitrary direction and termination. The robust one-dimensional Majorana edge mode dispersing across the entire superconducting gap has slightly different localization length along the different directions of the step edges. We propose a simple model of nodal topological superconductivity pertinent to TMDs that captures the essential phenomenon of the one-dimensional edge mode along different directions and edge terminations. This is the first observation of Majorana edge mode in an intrinsically topologically superconducting material, marking a significant advance towards engineering two-dimensional devices for quantum computation.