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

• Published in: Communications physics Vol. 6; no. 1; pp. 202 - 12
• Main Authors: Piatti, Erik, Prando, Giacomo, Meinero, Martina, Tresca, Cesare, Putti, Marina, Roddaro, Stefano, Lamura, Gianrico, Shiroka, Toni, Carretta, Pietro, Profeta, Gianni, Daghero, Dario, Gonnelli, Renato S.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 05.08.2023; Nature Publishing Group; Nature Portfolio
• Subjects: 639/301/357/1018; 639/766/119/1003; 639/766/119/995; Charge density waves; Doping; Ground state; Hydrides; Intercalation; Ionic liquids; Ions; Layered materials; Lithium; Phase diagrams; Physics; Physics and Astronomy; Pressure; Protonation; Room temperature; Superconductivity; Titanium; Transition metal compounds
• ISSN: 2399-3650; 2399-3650
• DOI: 10.1038/s42005-023-01330-w

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 (1 T -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. The key role played by hydrogen (H) in the near-to-room temperature superconductivity of hydrides at megabar pressures suggests that H doping could produce similar effects in materials at ambient pressure. Here the authors show that ionic gate-driven H intercalation in the layered compound TiSe 2 induces a superconducting phase with features distinct from those obtained through other doping techniques.