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

Xinshu Zhang; Yuanyuan Xu; T Halloran; Ruidan Zhong; C Broholm; R J Cava; N Drichko; N P Armitage

doi:10.1038/s41563-022-01403-1

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

Nat Mater. 2023 Jan;22(1):58-63. doi: 10.1038/s41563-022-01403-1. Epub 2022 Nov 21.

Authors

Xinshu Zhang¹, Yuanyuan Xu¹, T Halloran¹, Ruidan Zhong², C Broholm^{1

3

4}, R J Cava², N Drichko¹, N P Armitage^{5

6}

Affiliations

¹ Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA.
² Department of Chemistry, Princeton University, Princeton, NJ, USA.
³ NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD, USA.
⁴ Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA.
⁵ Institute for Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD, USA. npa@jhu.edu.
⁶ Canadian Institute for Advanced Research, Toronto, Ontario, Canada. npa@jhu.edu.

PMID: 36411349
DOI: 10.1038/s41563-022-01403-1

Abstract

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 BaCo₂(AsO₄)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 BaCo₂(AsO₄)₂ is a promising QSL candidate.

Grants and funding

DE-SC0019331/U.S. Department of Energy (DOE)