2025/01/16 by Ying Fu, Han Ge, Fu, Ying +25
Materials Science · #Crystal Structures and Properties #FOS: Physical sciences #Magnetism in coordination complexes #Solid-state spectroscopy and crystallography #Strongly Correlated Electrons (cond-mat.str-el)
paper · pdf · doi:10.48550/arxiv.2501.09619
openalex publication_date 2025/01/16 · openalex created_date 2025/01/18 · openalex updated_date 2026/07/28
We investigate the magnetic phase diagram of the bilayer triangular antiferromagnet K2Co2(SeO3)3, revealing a rich interplay among geometric frustration, bilayer coupling, and symmetry-driven phenomena. High-field magnetization measurements show fractional magnetization plateaus at 1/3, 1/2, 2/3, and 5/6 of the saturation magnetization. To elucidate the experimental magnetic phase diagram at low fields, we propose that K2Co2(SeO3)3 can be described as an easy-axis triangular weak-dimer antiferromagnet. We emphasize the critical role of the emergent U(1) ⊗ S3 symmetry, where S3 = ℤ3 ⊗ ℤ2d, in determining the magnetic phases at low fields. The remarkable agreement between the experimental and theoretical phase diagrams suggests that the phase transitions are governed by this symmetry. Notably, our combined experimental and theoretical results identify a Berezinskii-Kosterlitz-Thouless (BKT) phase region at finite fields. These findings provide new insights into the phase structure of frustrated magnets and establish K2Co2(SeO3)3 as a compelling platform for exploring unconventional quantum phenomena in U(1) ⊗ S3 systems.