# Superconductivity in Li-intercalated 1T-SnSe2 driven by electric-field gating

## TL;DR

This study demonstrates that electric-field gating can induce superconductivity in ultrathin Li-intercalated SnSe2, with a maximum T c of 6.2 K, by increasing carrier density and enhancing electron-phonon interactions.

## Contribution

It introduces a novel method of inducing superconductivity in layered SnSe2 via Li intercalation and electric-field gating, revealing the role of electron-phonon interactions.

## Key findings

- Superconductivity at 4.8 K induced in Li-intercalated SnSe2.
- Optimal T c of 6.2 K achieved with S substitution.
- Li intercalation expands interlayer spacing and increases carrier density.

## Abstract

Creating carrier reservoirs in layered compounds can effectively tune the carrier density, which often induces a variety of emergent properties. Based on solid-ion-conductor gating technique, we successfully induce superconductivity of 4.8 K in ultrathin Li-intercalated SnSe2 samples. The Li+ ions are driven in between interspacing of SnSe2 layers and form a single reservoir layer to provide electrons. In addition, a dome-like T c is found through substituting of S for Se, where the optimal T c is 6.2 K for SnSe1.8S0.2. Density functional theory calculations confirm that the intercalated LiSnSe2 is thermodynamically favorable, where the intercalation of Li expands the interlayer spacing by 10% and increases the carrier density by two orders of magnitude. Meanwhile the calculated results reveal that the enhanced electron-phonon interaction due to softened phonon determines the occurrence of superconductivity. Our results demonstrate that this strategy is very effective to explore superconductors in layered materials with narrow bandgap.