Superconductivity induced by gate-driven hydrogen intercalation in the charge-density-wave compound 1T-TiSe2

TL;DR

This study demonstrates that gate-driven hydrogen intercalation in 1T-TiSe2 induces a superconducting phase alongside charge-density waves, revealing a novel method to control electronic states in layered materials at ambient conditions.

Contribution

It introduces a new approach to induce and control superconductivity in 1T-TiSe2 through ionic liquid gating-driven hydrogen intercalation, distinct from traditional doping methods.

Findings

Hydrogen intercalation induces superconductivity in 1T-TiSe2.

The superconducting phase coexists with charge-density waves.

High H doping causes a full reconstruction of the bandstructure.

Abstract

Hydrogen (H) plays a key role in the near-to-room temperature superconductivity of hydrides at megabar pressures. This suggests that H doping could have similar effects on the electronic and phononic spectra of materials at ambient pressure as well. Here, we demonstrate the non-volatile control of the electronic ground state of titanium diselenide (1T-TiSe$_2$) via ionic liquid gating-driven H intercalation. This protonation induces a superconducting phase, observed together with a charge-density wave through most of the phase diagram, with nearly doping-independent transition temperatures. The H-induced superconducting phase is possibly gapless-like and multi-band in nature, in contrast with those induced in TiSe$_2$ via copper, lithium, and electrostatic doping. This unique behavior is supported by ab initio calculations showing that high concentrations of H dopants induce a full reconstruction of the bandstructure, although with little coupling between electrons and high-frequency H phonons. Our findings provide a promising approach for engineering the ground state of transition metal dichalcogenides and other layered materials via gate-controlled protonation.