Iron-chalcogenide based superconductor have set a new paradigm in exploring microscopic mechanism of superconductivity and a race to discover high-Tc interfacial superconductor. It also offer a new platform to realize pristine topological superconductivity and Majorana bound state at relatively high temperature [1, 2].
In this talk, I will discuss our recent findings of atomic scale spin structure and superconductivity in single layer Fe-chalcogenide films grown on Bi-based 3D topological insulator, briefly explained as follows. At first, we show the existence of non-collinear antiferromagnetic state in a single unit-cell FeTe, as revealed by spin-polarized scanning tunnelling spectroscopy. A detailed investigation of the temperature, magnetic field and spatial evolution of the electronic structure across the magnetic domains indicates that the unit-cell of FeTe is in very close proximity to a superconducting phase transition that coexisting with the anti-ferromagnetism [3, 4]. This will followed by discussion in spatial distribution of superconductivity in single layer FeSe0.5Te0.5 with higher critical temperature, which provides an ideal platform to study exotic phase in close proximity to a topological insulator [5].
Finally, I will discuss our unique approach to create a metallic based topological superconductor in combination with surface state of large Rashba spin-orbit coupling and an s -wave superconductor.