Observation of Edge Supercurrent in SnTe(111) Thin Films

SnTe is a topological crystalline insulator (TCI) characterized by an even number nontrivial Dirac surface states on high-symmetry crystal surfaces. Theoretical calculations predict that SnTe(111) films can host a 2D topological insulator (TI) phase within a specific thickness range. In this work, we employ molecular beam epitaxy (MBE) to grow SnTe(111) films on InP substrates and fabricate Josephson junction (JJ) devices. By measuring the Fraunhofer patterns, we find that the supercurrent travels exclusively through two edge channels with a skewed current-phase relation and exhibits strong resilience to an external magnetic field. By combining temperature-dependent critical current measurements, angle-resolved photoemission spectroscopy, and density function theory calculations, we demonstrate the emergence of a 2D TI phase in SnTe(111) films with thicknesses between 8 and 15 bilayers. Our work provides direct evidence for the 2D TI phase in SnTe(111) thin films and establishes SnTe(111)-based JJs as a promising platform for exploring Majorana physics.