2025/03/28 by Haoran Lin, Lin, Haoran, C. Jacobs +33 · 4 citations
Materials Science · Physics and Astronomy · #Electronic and Structural Properties of Oxides #FOS: Physical sciences #Iron-based superconductors research #Strongly Correlated Electrons (cond-mat.str-el) #Superconductivity (cond-mat.supr-con) #Topological Materials and Phenomena
paper · pdf · doi:10.48550/arxiv.2503.22888
openalex publication_date 2025/03/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A topological superconductor, characterized by either a chiral order parameter or a chiral topological surface state in proximity to bulk superconductivity, is foundational to topological quantum computing. As in other topological phases of matter, electronic correlations can tune topological superconductivity via modifications of the low-energy Fermiology. Such tuning has not been realized so far. Here we uncover a unique topological superconducting phase in competition with electronic correlations in 10-unit-cell thick FeTexSe1-x films grown on SrTiO3 substrates. When the Te content x exceeds 0.7, we observe a rapid increase of the effective mass for the Fe dxy band, with the emergence of a superconducting topological surface state confirmed by high-resolution angle-resolved photoemission spectroscopy; however, near the FeTe limit, the system enters an incoherent regime where the topological surface state becomes unidentifiable and superconductivity is suppressed. Theory suggests that the electron-electron interactions in the odd-parity xy- band with a strong dxy character lead to an orbital-selective correlated phase. Our work establishes FeTexSe1-x thin films as a unique platform where electronic correlations sensitively modulate topological superconductivity, suggesting opportunities to use tunable electron-electron interactions to engineer new topological phases in a broad class of materials.