Honeycomb-structure RuI3 , a new quantum material related to α-RuCl3.

The layered honeycomb lattice material α-RuCl3 has emerged as a prime candidate for displaying the Kitaev quantum spin liquid state and as such has attracted much research interest. Here we describe a new layered honeycomb lattice polymorph of RuI3 , a material that is strongly chemically and structurally related to α-RuCl3 . The material is synthesized at moderately elevated pressures and is stable under ambient conditions. Preliminary characterization reveals that it is a metallic conductor, with the absence of long-range magnetic order down to 0.35 K and an unusually large T-linear contribution to the heat capacity. We propose that this phase, with a layered honeycomb lattice and strong spin-orbit coupling, provides a new route for the characterization of quantum materials. This article is protected by copyright. All rights reserved.