Electronic and magnetic properties of the RuX3 (X = Cl, Br, I) family: two siblings—and a cousin?

• Published in: npj quantum materials Vol. 7; no. 1
• Main Authors: Kaib, David A. S., Riedl, Kira, Razpopov, Aleksandar, Li, Ying, Backes, Steffen, Mazin, Igor I., Valentí, Roser
• Format: Journal Article
• Language: English
• Published: United States Nature Publishing Group 29-07-2022
• Subjects: Materials Science; Physics
• ISSN: 2397-4648; 2397-4648

Abstract Motivated by reports of metallic behavior in the recently synthesized RuI3, in contrast to the Mott-insulating nature of the actively discussedα-RuCl3, as well as RuBr3, we present a detailed comparative analysis of the electronic and magnetic properties of this family of trihalides. Using a combination of first-principles calculations and effective-model considerations, we conclude that RuI3, similarly to the other two members, is most probably on the verge of a Mott insulator, but with much smaller magnetic moments and strong magnetic frustration. We predict the ideal pristine crystal of RuI3to have a nearly vanishing conventional nearest-neighbor Heisenberg interaction and to be a quantum spin liquid candidate of a possibly different kind than the Kitaev spin liquid. In order to understand the apparent contradiction to the reported resistivityρ, we analyze the experimental evidence for all three compounds and propose a scenario for the observed metallicity in existing samples of RuI3. Furthermore, for the Mott insulator RuBr3,we obtain a magnetic Hamiltonian of a similar form to that in the much-discussedα-RuCl3and show that this Hamiltonian is in agreement with experimental evidence in RuBr3.