Magnetic versus nonmagnetic polymorphs of RuBr${}_3$ under pressure

Abstract

Pressure evolution of the crystal structure and magnetism of the honeycomb $\alpha$-RuBr${}_3$ is studied using high-pressure x-ray diffraction, magnetometry, and density-functional band-structure calculations. Hydrostatic compression transforms antiferromagnetic $\alpha$-RuBr${}_3$ ($R\bar{3}$) into paramagnetic ${\alpha }^{\prime }$-RuBr${}_3$ ($P\bar{1}$) where short Ru-Ru bonds cause magnetism collapse above 1.3 GPa at 0 K and 2.5 GPa at 295 K. Below this critical pressure, the Néel temperature of $\alpha$-RuBr${}_3$ increases with the slope of 1.8 K/GPa. Pressure tunes $\alpha$-RuBr${}_3$ away from the Kitaev limit, whereas increased third-neighbor in-plane coupling and interlayer coupling lead to a further stabilization of the collinear zigzag state. Both $\alpha$- and ${\alpha }^{\prime }$-RuBr${}_3$ are metastable at ambient pressure, but their transformation into the thermodynamically stable $\beta$-polymorph is kinetically hindered at room temperature.

8 pages + Supplemental Material: published version

References in corpus (8)

• Mott Insulators in the Strong Spin-Orbit Coupling Limit: From Heisenberg to a Quantum Compass and Kitaev Models
• Models and Materials for Generalized Kitaev Magnetism
• Pseudospin exchange interactions in d^7 cobalt compounds: Possible realization of the Kitaev model
• Beyond Kitaev physics in strong spin-orbit coupled magnets
• Magnetism of Kitaev spin-liquid candidate material RuBr${}_3$
• Revealing frustrated local moment model for pressurized hyperhoneycomb iridate: paving a way toward quantum spin liquid
• Magnetism in Kitaev Quantum Spin Liquid Candidate RuBr${}_3$
• Interplay of magnetism and dimerization in pressurized Kitaev material $\beta$-Li${}_2$IrO${}_3$

Cited by in corpus (2)

• Anisotropy of the zigzag order in the Kitaev honeycomb magnet $\alpha$-RuBr${}_3$
• Pressure-dependent magnetism of the Kitaev candidate Li${}_2$RhO${}_3$