Materializing rival ground states in the barlowite family of kagome magnets: quantum spin liquid, spin ordered, and valence bond crystal states
The spin- 1 2 kagome antiferromagnet is considered an ideal host for a quantum spin liquid (QSL) ground state. We find that when the bonds of the kagome lattice are modulated with a periodic pattern, new quantum ground states emerge. Newly synthesized crystalline barlowite (Cu 4 (OH) 6 FBr) and Zn-s...
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Published in | npj quantum materials Vol. 5; no. 1 |
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Main Authors | , , , , , , , , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
London
Nature Publishing Group UK
01.01.2020
Nature Publishing Group |
Subjects | |
Online Access | Get full text |
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Summary: | The spin-
1
2
kagome antiferromagnet is considered an ideal host for a quantum spin liquid (QSL) ground state. We find that when the bonds of the kagome lattice are modulated with a periodic pattern, new quantum ground states emerge. Newly synthesized crystalline barlowite (Cu
4
(OH)
6
FBr) and Zn-substituted barlowite demonstrate the delicate interplay between singlet states and spin order on the spin-
1
2
kagome lattice. Comprehensive structural measurements demonstrate that our new variant of barlowite maintains hexagonal symmetry at low temperatures with an arrangement of distorted and undistorted kagome triangles, for which numerical simulations predict a pinwheel valence bond crystal (VBC) state instead of a QSL. The presence of interlayer spins eventually leads to an interesting pinwheel
q
= 0 magnetic order. Partially Zn-substituted barlowite (Cu
3.44
Zn
0.56
(OH)
6
FBr) has an ideal kagome lattice and shows QSL behavior, indicating a surprising robustness of the QSL against interlayer impurities. The magnetic susceptibility is similar to that of herbertsmithite, even though the Cu
2+
impurities are above the percolation threshold for the interlayer lattice and they couple more strongly to the nearest kagome moment. This system is a unique playground displaying QSL, VBC, and spin order, furthering our understanding of these highly competitive quantum states. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 AUTHOR CONTRIBUTIONS R.W.S. and Y.S.L. conceived the study, interpreted the data, and wrote the manuscript with contributions and comments from all authors. R.W.S. synthesized barlowite 2 and all Zn-substituted barlowite samples; performed and analyzed X-ray and neutron diffraction measurements; and performed and analyzed magnetic susceptibility and heat capacity measurements. W.H. synthesized barlowite 1 and performed and analyzed neutron scattering measurements. J.M.J., C.J.T. and J.W. aided at beamtimes and with data analysis. Y.-F.J. and H.C.J. performed numerical calculations. J.P.S. synthesized herbertsmithite. S.G.W., Y.-S.C., S.J.T., A.A.A., Y.Z., G.X. and J.W.L. aided at beamtimes. |
ISSN: | 2397-4648 2397-4648 |
DOI: | 10.1038/s41535-020-0222-8 |