Strongly Electron-Correlated Semimetal RuI₃ with a Layered Honeycomb Structure

Abstract

A polymorph of RuI$_3$ synthesized under high pressure was found to have a\ntwo-layered honeycomb structure. The resistivity of RuI$_3$ exhibits a\nsemimetallic behavior, in contrast to insulating properties in\n$\\alpha$-RuCl$_3$. In addition, Pauli paramagnetic behavior was observed in the\ntemperature dependence of a magnetic susceptibility and a nuclear spin-lattice\nrelaxation rate 1/$T_1$. The band structure calculations indicate that\ncontribution of the I 5$p$ components to the low-energy $t_\\mathrm{2g}$ bands\neffectively decreases Coulomb repulsion, leading to semimetallic properties.\nThe physical properties also suggest strong electron correlations in RuI$_3$.\n