Publications Repository - Helmholtz-Zentrum Dresden-Rossendorf

Pressure evolution of the crystal structure and magnetism of the honeycomb α-RuBr₃ is studied using high-pressure x-ray diffraction, magnetometry, and density-functional band-structure calculations. Hydrostatic compression transforms antiferromagnetic α-RuBr₃ (R-3) into paramagnetic α′-RuBr₃ (P-1) where short Ru–Ru bonds cause magnetism collapse above 1.3GPa at 0K and 2.5GPa at 295 K. Below this critical pressure, the Neel temperature of α-RuBr₃ increases with the slope of 1.8K/GPa. Pressure tunes α-RuBr₃ away from the Kitaev limit, whereas increased thirdneighbor in-plane coupling and interlayer coupling lead to a further stabilization of the collinear zigzag state. Both α- and α′-RuBr₃ are metastable at ambient pressure, but their transformation into the thermodynamically stable β-polymorph is kinetically hindered at room temperature.