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arXiv · 1412.5908

Spin excitations in the two-dimensional strongly coupled dimer system malachite

E. Canevet·B. Fak·R. K. Kremer·J. H. Chun·M. Enderle·E. E. Gordon·J. L. Bettis·M. -H. Whangbo·J. W. Taylor·D. T. Adroja
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Abstract

The mineral malachite, Cu2(OD)2CO3, has a quantum spin-liquid ground state and no long-range magnetic order down to at least T=0.4 K. Inelastic neutron scattering measurements show that the excitation spectrum consists of dispersive gapped singlet-triplet excitations, characteristic of spin-1/2 dimer-forming Heisenberg antiferromagnets. We identify a new two-dimensional dimerized coupling scheme with strong interdimer coupling J'/J1~0.3 that places malachite between strongly coupled alternating chains, square lattice antiferromagnets, and infinite-legged ladders. The geometry of the interaction scheme resembles the staggered dimer lattice, which may allow unconventional quantum criticality.

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E. Canevet, B. Fak, R. K. Kremer, J. H. Chun, M. Enderle, E. E. Gordon, J. L. Bettis, M. -H. Whangbo, J. W. Taylor, D. T. Adroja. 2014-12-18. Spin excitations in the two-dimensional strongly coupled dimer system malachite. https://doi.org/10.1103/physrevb.91.060402

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