A magnetic continuum in the cobalt-based honeycomb magnet BaCo2(AsO4)2

• Published in: Nature materials 2023-01, Vol.22 (1), p.58-63
• Main Authors: Zhang, Xinshu, Xu, Yuanyuan, Halloran, T., Zhong, Ruidan, Broholm, C., Cava, R. J., Drichko, N., Armitage, N. P.
• Format: Article
• Language: English
• Subjects: 639/766/119/2795; 639/766/119/997; Biomaterials; Chemistry; Chemistry and Materials Science; Cobalt; Condensed Matter Physics; Hexagonal lattice; Magnetic fields; Materials Science; Nanotechnology; Optical and Electronic Materials; Physics; Spectroscopy; Spectrum analysis; Spin liquid; Time domain analysis; Transition metals
• ISSN: 1476-1122; 1476-4660
• DOI: 10.1038/s41563-022-01403-1

Quantum spin liquids (QSLs) are topologically ordered states of matter that host fractionalized excitations. A particular route towards a QSL is via strongly bond-dependent interactions on the hexagonal lattice. A number of Ru- and Ir-based candidate Kitaev QSL materials have been pursued, but all have appreciable non-Kitaev interactions. Using time-domain terahertz spectroscopy, we observed a broad magnetic continuum over a wide range of temperatures and fields in the honeycomb cobalt-based magnet BaCo 2 (AsO 4 ) 2 , which has been proposed to be a more ideal version of a Kitaev QSL. Applying an in-plane magnetic field of ~0.5 T suppresses the magnetic order, and at higher fields, applying the field gives rise to a spin-polarized state. Under a 4 T magnetic field that was oriented principally out of plane, a broad magnetic continuum was observed that may be consistent with a field-induced QSL. Our results indicate BaCo 2 (AsO 4 ) 2 is a promising QSL candidate. The authors present time-domain terahertz spectroscopy measurements on BaCo 2 (AsO 4 ) 2 , a promising 3 d transition-metal-based quantum spin liquid candidate.