Two-Fold Anisotropic Superconductivity in Non-centrosymmetric Sn₄Au Single Crystals

We report the synthesis and characterization of Sn₄Au single crystals exhibiting a two-fold anisotropic superconducting state below T_c = 2.3 K. Through angle-resolved magnetotransport and magnetization measurements, we identify an upper critical field anisotropy ratio Γ = 1.26, with H_c2^∥(0) = 970 Oe (in-plane) and H_c2^⟂(0) = 770 Oe (out-of-plane). The observed anisotropy arises from the layered non-centrosymmetric Aea2 structure, which hosts Rashba-Dresselhaus spin-orbit coupling. Ginzburg-Landau analysis confirms the two-fold symmetry, while coherence lengths (ξ_∥ = 58 nm, ξ_⟂ = 74 nm) reflect anisotropic vortex pinning. These results establish Sn₄Au as a model system for studying topological superconductivity in non-centrosymmetric materials.