Effect of delithiation on the dimer transition of the honeycomb-lattice ruthenate Li$_{2-x}$RuO$_3$

TL;DR

This study investigates how removing lithium from Li$_2$RuO$_3$ induces a new phase with distinct magnetic and structural properties, revealing complex dimer formations in the honeycomb ruthenate.

Contribution

It is the first to characterize the magnetic and structural properties of the delithiated D-phase in Li$_{2-x}$RuO$_3$, highlighting the formation of mixed-valence dimers.

Findings

Identification of Ru$^{4+}$-Ru$^{4+}$ and Ru$^{5+}$-Ru$^{5+}$ dimers

Discovery of a superlattice in the D-phase

Evidence of complex bonding configurations

Abstract

The honeycomb-lattice ruthenate Li$_2$RuO$_3$ is made heavily Li-deficient by chemical oxidation by iodine. The delithiation triggers a different phase Li$_{2-x}$RuO$_3$, the "D-phase", with superlattice. For the first time we disclose the magnetic and structural properties of the D-phase in the dimer-solid state. The low temperature magnetic susceptibility and the bond lengths indicate a bonding configuration consisting of both Ru$^{4+}$-Ru$^{4+}$ and Ru$^{5+}$-Ru$^{5+}$ dimers.