Superconductor Fe(Se,Te) Monolayer: an Intrinsic, Scalable and Electrically-tunable Majorana Platform*

A monolayer of the high-T_c superconductor FeTe_1-xSe_x has been predicted to realize a topologically non-trivial state with helical edge modes at its boundary, providing a novel intrinsic system to search for topological superconductivity and Majorana zero modes. Evidence in favor of a topological phase transition and helical edge modes has been given in recent experiments. We propose to create Majorana zero modes by applying an in-plane magnetic field to the FeTe_1-xSe_x monolayer and by tuning the local chemical potential via electric gating. We demonstrate that, for appropriate parameter regimes, Majorana zero modes can exist at several different locations, including the corner between two perpendicular edges, the domain wall of chemical potentials at one edge, and certain type of tri-junction in the 2D bulk. The scalability and electrical tunability of our proposal render FeTe_1-xSe_x monolayer a promising Majorana platform which is in reach of contemporary experimental capability.