Spacing Dependent and Doping Independent Superconductivity in Intercalated 1T Two Dimensional SnSe2

TL;DR

This study demonstrates that in 1T-SnSe2, superconductivity is strongly dependent on interlayer spacing and doping, with cointercalation of polar molecules significantly enhancing the critical temperature, revealing new pathways for exploring electron correlations.

Contribution

It introduces a novel chemical intercalation method using polar organic molecules to enhance superconductivity in 2D SnSe2, independent of doping levels.

Findings

Superconductivity up to 7.6 K achieved in intercalated 1T-SnSe2.

Tc scales with interlayer spacing, not doping concentration.

Cointercalation with polar molecules significantly boosts Tc.

Abstract

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 interlayer spacing d in the chemically intercalated two dimensional 1T-SnSe2 phase. We found, for the first time in the two dimensional SnSe2, that polar organic molecules cointercalated with the alkali metal Li into the basal layers, thus significantly enhancing the superconducting Tc. We observed that the Tc scales with the basal spacing distance, meanwhile being almost independent of x in Lix(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 two dimensional material.