Insulator-metal transition in Ru(Br1-x Ix)3 with honeycomb structure

We investigate electronic properties of solid solution Ru(Br1-xIx)3 with honeycomb structure which bridges the spin-orbit-entangled Mott insulator RuBr3 and strongly electron-correlated semimetal RuI3. We find a first-order insulator-metal transition at x∼0.85 triggered by increased d-p hybridization and formation of interlayer I-I bonds. We also observe switching of the magnetic structure at x=0.30. In the metallic phase, we find critical mass enhancement leading to the carrier localization. This study furthers understanding of the Mott transition in a strongly spin-orbit-entangled system.