Evolution of the Intertwining Correlated Topological Phases in Iron-Based Superconductor Fe(Te,Se)

Multiple topological electronic phases can coexist within a single quantum material and induce different topological superconducting states, offering deeper insights into the interplay of topological superconducting states and Majorana modes, which may also be influenced and modified by the correlation effect. Iron-based superconductors, with both topological states and correlation effects, are an ideal platform to study these phenomena. Here, with high-resolution angle-resolved photoelectron spectroscopy, we directly resolve two distinct intertwining topological states in iron-based superconductor Co-doped Fe(Te,Se) and study their evolution with electron doping. We identify a region where both topological insulator surface states and topological Dirac semimetal states intersect with the Fermi level. The topological states are affected by the strong correlation effect and are isolated from the trivial bulk states. The evolution between distinct topological phases offers a good opportunity to study various Majorana modes from different superconducting phases according to the theoretical analysis. Our findings establish an ideal platform for exploring the interaction between multiple topological superconducting states and related Majorana modes.