Tuning topology and strong correlation in thin film FeTe_xSe_1-x

FeTe_xSe_1-x(FTS) has emerged as an intriguing system that exhibits both non-trivial topology and superconductivity. This naturally positions FTS as a promising candidate for investigating topological superconductivity and Majorana fermions. In our study, we combine molecular-beam epitaxy (MBE) and angle-resolved photoemission spectroscopy (ARPES) to study the evolution of electronic correlations and band topology as a function of the tellurium(Te) concentration. We report the evidence for non-trivial topological surface states in MBE grown FeTe_xSe_1-x thin films with x > 0.7. Additionally, our measurements reveal increasing electronic correlations at the Brillouin zone corner as we approach the FeTe limit. This comprehensive investigation not only contributes to our understanding of the correlated physics in FTS but also underscores the potential of high-quality MBE-grown FTS thin film as a flexible platform for quantum computing devices.