Superconductivity induced by gate-driven hydrogen intercalation in the charge-density-wave compound 1T-TiSe2
Erik Piatti, Giacomo Prando, Martina Meinero, Cesare Tresca, M. Putti, Stefano Roddaro, G. Lamura, T. Shiroka, P. Carretta, G. Profeta, D. Daghero, R. S. Gonnelli
Abstract
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 (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.