Emergent unconventional superconductivity in an aged α-Sn thin film

Superconductivity in topological materials offers a promising route to topological superconductors, which host robust exotic states for low-power spintronics and quantum devices. Here we report the emergence of intrinsic, unconventional superconductivity in a topologically nontrivial α-Sn thin film that develops twenty months after growth. This superconducting state exhibits a large in-plane critical magnetic field beyond the Pauli limit and an unusual twofold-symmetric angular dependence, consistent with type-II Ising superconductivity in centrosymmetric α-Sn. Magnetotransport measurements, Shubnikov–de Haas oscillations and first-principles calculations further reveal the appearance of an additional Fermi-surface band with linear dispersion, enhanced mobility and a relatively large effective mass in the superconducting phase. Our results suggest that α-Sn is a possible promising platform for topological superconductivity and show that aging-driven elemental diffusion and electronic reconstruction can trigger a quantum phase transition in an elemental Dirac semimetal.