US scientists develop ‘control knob’ to tune quantum superconductor

Researchers from the University of Chicago’s Pritzker School of Molecular Engineering and West Virginia University have developed a novel method to control the quantum properties of ultra-thin films of iron telluride selenide, a topological superconductor. By precisely tuning the ratio of tellurium to selenium in films just 10 atomic layers thick, they demonstrated a "control knob" that switches the material between topologically trivial and non-trivial phases. When tellurium content exceeds 70%, the material exhibits protected surface states essential for quantum computing. Unexpectedly, at very high purity (pure iron telluride), the topological surface state disappears, reverting to a trivial phase, highlighting the tunability of quantum materials through electron correlations. This discovery emphasizes the role of electronic correlations in engineering topological quantum matter, showing that quantum states are not fixed but can be finely adjusted. Compared to bulk crystals, these ultra-thin films are more uniform and easier to integrate into devices. They also operate at