# Hydrated lithium intercalation into the Kitaev spin liquid candidate material $\alpha-$RuCl$_3$

## TL;DR

This study investigates how hydration and lithium intercalation affect the structural, electronic, and magnetic properties of $ ext{α-RuCl}_3$, revealing new crystal phases, charge ordering phenomena, and suppression of antiferromagnetic order.

## Contribution

It provides the first detailed analysis of hydrated lithium-intercalated $ ext{α-RuCl}_3$ structures and their impact on magnetic and electronic behaviors, advancing understanding of Kitaev candidate materials.

## Key findings

- Identified mono-layer and bi-layer hydrated crystal structures.
- Observed charge order formation at 200-270 K.
- Suppressed antiferromagnetic order down to 2 K in bi-layer hydrated sample.

## Abstract

We study on transport and magnetic properties of hydrated and lithium-intercalated $\alpha$-RuCl$_3$, Li$_x$RuCl$_3 \cdot y$H$_2$O, for investigating the effect on mobile-carrier doping into candidate materials for a realization of a Kitaev model. From thermogravitometoric and one-dimensional electron map analyses, we find two crystal structures of this system, that is, mono-layer hydrated Li$_x$RuCl$_3 \cdot y$H$_2$O~$(x\approx0.56, y\approx1.3)$ and bi-layer hydrated Li$_x$RuCl$_3 \cdot y$H$_2$O~$(x\approx0.56, y\approx3.9)$. The temperature dependence of the electrical resistivity shows a temperature hysteresis at 200-270 K, which is considered to relate with a formation of a charge order. The antiferromagnetic order at 7-13 K in pristine $\alpha$-RuCl$_3$~ is successfully suppressed down to 2 K in bi-layer hydrated Li$_x$RuCl$_3 \cdot y$H$_2$O, which is sensitive to not only an electronic state of Ru but also an interlayer distance between Ru-Cl planes.