Enhancement of superconductivity in organic-inorganic hybrid topological materials

Inducing or enhancing superconductivity in topological materials is an important route toward topological superconductivity. Reducing the thickness of transition metal dichalcogenides (e.g. WTe₂ and MoTe₂) has provided an important pathway to engineer superconductivity in topological matters. However, such monolayer sample is difficult to obtain, unstable in air, and with extremely low T_c. Here we report an experimentally convenient approach to control the interlayer coupling to achieve tailored topological properties, enhanced superconductivity and good sample stability through organic-cation intercalation of the Weyl semimetals MoTe₂ and WTe₂. The as-formed organic-inorganic hybrid crystals are weak topological insulators with enhanced T_c of 7.0 K for intercalated MoTe₂ (0.25 K for pristine crystal) and 2.3 K for intercalated WTe₂ (2.8 times compared to monolayer WTe₂). Such organic-cation intercalation method can be readily applied to many other layered crystals, providing a new pathway for manipulating their electronic, topological and superconducting properties.