Self-assembled SnS/TaS₂ superconducting superlattice with non-trivial band topology

Intrinsic topological superconductors have garnered significant attention for their potential to harbor novel quantum phenomena. However, the limited availability of suitable material systems has hindered progress in this field. Here, we present the synthesis and characterization of high-quality self-assembled SnS/TaS₂ (SnTaS₃) superlattice, which exhibits superconductivity alongside non-trivial band topology. Temperature-dependent magnetization susceptibility and electrical transport results confirm SnTaS₃ as a type-II superconductor with a critical transition temperature T_c of 3 K. Interestingly, this superconductivity can be turned off via an innovative solid proton gate technique, and a new superconducting state with a T_c of ~ 2.3 K emerges when the gating voltage reaches −9.47 V. Heat capacity measurements reveal strong electronic correlations within this material, which is further supported by angle-resolved photoemission spectroscopy and first-principles calculations, underscoring the effect of topological flat bands and Van Hove singularity. Our research introduces a promising self-assembled material platform, adeptly positioned to delve into the quest for topological superconductors.