Spacing dependent and cation doping independent superconductivity in intercalated 1T 2D SnSe2

The weak van der Waals interlayer interactions in the transition metal dichalcogenide (TMD) materials have created a rich platform to study their exotic electronic properties through chemical doping or physical gating techniques. We reported bulk superconductivity up to 7.6 K through careful manipulation of the charge carrier density and basal spacing d in the chemically intercalated 2D 1T-SnSe2 phase. We found, for the first time in the 2D SnSe2, that polar organic molecules cointercalated with the alkali metal Li into the basal layers, thus significantly enhancing the superconducting T-c. We observed that the T-c scales with the basal spacing distance, meanwhile being almost independent of x in Li-x(THF) ySnSe2 system. Our results offers a new general chemical route to study the rich electron correlations and the interplay of charge density wave and unconventional superconductivity in the 2D material.