Ionic liquid gating induced self-intercalation of transition metal chalcogenides

Ionic liquids provide versatile pathways for controlling the structures and properties of quantum materials. Previous studies have reported electrostatic gating of nanometer-thick flakes leading to emergent superconductivity, insertion or extraction of protons and oxygen ions in perovskite oxide films enabling the control of different phases and material properties, and intercalation of large-sized organic cations into layered crystals giving access to tailored superconductivity. Here, we report an ionic-liquid gating method to form three-dimensional transition metal monochalcogenides (TMMCs) by driving the metals dissolved from layered transition metal dichalcogenides (TMDCs) into the van der Waals gap. We demonstrate the successful self-intercalation of PdTe2 and NiTe2, turning them into high-quality PdTe and NiTe single crystals, respectively. Moreover, the monochalcogenides exhibit distinctive properties from dichalcogenides. For instance, the self-intercalation of PdTe2 leads to the emergence of superconductivity in PdTe. Our work provides a synthesis pathway for TMMCs by means of ionic liquid gating driven self-intercalation. Transition metal monochalcogenides have been predicted to host interesting superconducting and topological properties, but their synthesis remains challenging. Here, the authors report a self-intercalation method driven by ionic liquid gating to obtain PdTe and NiTe single crystals from PdTe2 and NiTe2, respectively.

Automated summary

In this study, the authors demonstrate a self-intercalation method driven by ionic liquid gating to obtain high-quality PdTe and NiTe single crystals from PdTe2 and NiTe2, respectively. This synthesis pathway for transition metal monochalcogenides provides new opportunities for exploring their unique properties, such as emergent superconductivity.