Magnetic phase competition in the highly frustrated iridate K₂IrCl₆

Frustrated magnetic materials have been studied to a great extent for their possibilities of realizing novel magnetic states such as spin ice or spin liquids [1]. K₂IrCl₆ is an exciting compound in a model antiferromagnet with face-centered-cubic frustration. Its extensive degeneracy could be lifted by various mechanisms including quantum or thermal fluctuations, further neighbor interaction, exchange anisotropies, and magneto-structural coupling, making it a model system to study the ground-state selection and explore the magnetic phase diagram on the fcc lattice. In this talk, I will discuss recent elastic and inelastic neutron scattering results on K₂IrCl₆ that indicate the coexistence of a minority type-I phase with k=(100) and a previously revealed type-III phase with k=(1 ½ 0). Given that the type-III magnetic order is the dominant phase, the type-I magnetic order could be stabilized through local deviations from cubic symmetry, quantum order-by-disorder effect, or both [2,3]. This study will help us understand the ground-state selections by various mechanisms so that we could possibly suppress the magnetic order and stabilize the quantum spin liquid state in frustrated magnets.

[1] L. Balents, Nature 464, 199 (2010)

[2] A. Aczel et al, Phys. Rev. B 99, 134417 (2019)

[3] R. Schick, arXiv:2206.12102 [cond-mat.str-el] (2022)