Exploring the Electronic and Magnetic Properties of New Metal Halides from Bulk to Two-Dimensional Monolayer: RuX3 (X=Br, I)

TL;DR

This study investigates the electronic and magnetic properties of RuBr3 and RuI3 in bulk and monolayer forms, revealing their potential for synthesis and unique magnetic behaviors influenced by dimensionality and computational methods.

Contribution

It demonstrates that RuBr3 and RuI3 can form stable two-dimensional layered structures and explores their magnetic states and electronic properties using advanced calculations.

Findings

Monolayers of RuX3 are likely synthesizable based on cleavage energy.

RuX3 monolayers prefer in-plane ferromagnetic spin orientation.

Magnetic ground states change from ferromagnetic to antiferromagnetic zigzag with U inclusion.

Abstract

Theoretical and experimental studies present that metal halogens in MX$_3$ forms can show very interesting electronic and magnetic properties in their bulk and monolayer phases. Many MX$_3$ materials have layered structures in their bulk phases, while RuBr$_3$ and RuI$_3$ have one-dimensional chains in plane. In this paper, we show that these metal halogens can also form two-dimensional layered structures in the bulk phase similar to other metal halogens, and cleavage energy values confirm that the monolayers of RuX$_3$ can be possible to be synthesised. We also find that monolayers of RuX$_3$ prefer ferromagnetic spin orientation in the plane for Ru atoms. Their ferromagnetic ground state, however, changes to antiferromagnetic zigzag state after U is included. Calculations using PBE+U with SOC predict indirect band gap of 0.70 eV and 0.32 eV for the optimized structure of RuBr$_3$ and RuI$_3$, respectively. Calculation based on the Monte Carlo simulations reveal interesting magnetic properties of RuBr$_3$, such as large Curie temperature against RuI$_3$, both in bulk and monolayer cases. Moreover, as a result of varying exchange couplings between neighboring magnetic moments, magnetic properties of RuBr$_3$ and RuI$_3$ can undergo drastic changes from bulk to monolayer. We hope our findings can be useful to attempt to fabricate the bulk and monolayer of RuBr$_3$ and RuI$_3$.