Ionic liquid gating induced self-intercalation of transition metal chalcogenides

TL;DR

This paper introduces a novel ionic-liquid gating technique to induce self-intercalation in layered transition metal dichalcogenides, transforming them into transition metal monochalcogenides with unique properties like superconductivity.

Contribution

It presents a new method for synthesizing transition metal monochalcogenides via ionic liquid gating driven self-intercalation, enabling property tuning.

Findings

Successful self-intercalation of PdTe2 and NiTe2 into PdTe and NiTe.

Emergence of superconductivity in PdTe after intercalation.

Distinctive properties of monochalcogenides compared to dichalcogenides.

Abstract

Ionic liquids provide versatile pathways for controlling the structures and properties of quantum materials. Previous studies have reported electrostatic gating of nanometre-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 PdTe$_2$ and NiTe$_2$, 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 PdTe$_2$ 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.