This paper presents a new, materials-focused way to predict topological superconductivity in real compounds. The authors build a multiscale computational pipeline that starts from first principles and ends with a direct test for topological superconducting states. They apply it to iron chalcogenides and to a proposed heterostructure based on FeSe on GaAs, and they also show that those heterostructures can be grown and structurally characterized in the lab.

At a high level the method ties together four pieces. First, density functional theory (DFT) is used to compute the material’s electronic structure from basic quantum mechanics. Second, the DFT results are turned into compact, low-energy models using Wannier functions so the problem becomes computationally manageable. Third, Bogoliubov–de Gennes theory is used to describe superconductivity on those low-energy models. Fourth, the authors compute a topological invariant called the Chern number using Matsubara Green’s functions, which tells whether a superconducting state is topological.

They use this approach to study both intrinsic topological superconductivity, where the material’s own pairing is topological, and proximity-induced topological superconductivity, where a non-topological material acquires pairing from a nearby superconductor. The specific systems analyzed are bulk-like and monolayer FeTeSe, and FeSe/GaAs heterostructures. These are multiorbital materials, meaning several electron orbitals contribute near the Fermi level, which the framework treats explicitly.

From the calculations the authors identify several electronic features that favor robust topological superconductivity. These include Rashba-active states near the Fermi level (states with a spin splitting that appears when inversion symmetry is broken), strong induced superconducting pairing, and substantial orbital hybridization between parts of the electronic structure that carry strong spin–orbit effects and parts that carry pairing. Using these ideas, they predict multiple topological superconducting phases in Fe-based materials and highlight FeSe/GaAs heterostructures as particularly promising because the predicted topological transitions occur at chemical potentials and magnetic (Zeeman) fields that are accessible in experiments.