Two-fold symmetric anisotropy of the superconducting phase of Fe Te0.5 Se0.5/Bi2 Te3 thin film

We report the epitaxial MBE-growth of FeTe0.5Se0.5 (a topological superconductor)/Bi2Te3 (a topological insulator) thin film on sapphire substrate. From the electrical transport measurements, we show that the critical current and the longitudinal resistance (measured at close to the critical temperature) of the system, are two-fold symmetric, in presence of a parallel magnetic field. Moreover, the anisotropy completely disappears in the normal state, at 15K, which clearly indicates that the anisotropy is the intrinsic property of the superconducting phase. Thus, our result shows an unconventional superconductivity in a heterostructure of an Iron based SC and a topological insulator, making it a potential candidate for topological quantum computation.